I. .
II. .
III. .
P(x) = a0xn + a1xn 1 + a2xn 2 + + an 1x + an,
n , a0, a1,, an , .
P(x) = 0, P(x) , .
P1(x) / Q1(x) + P2(x) / Q2(x) + + Pm(x) / Qm(x) = 0,
P1(x), P2(x), ,Pm(x), Q1(x), Q2(x), , Qm(x) , .
P (x) / Q (x) = 0, P (x) Q (x) (Q (x) ¹ 0), P (x) = 0 , Q (x) ¹ 0.
ax+b=0, a b , .
a¹ 0, : x = -b /a.
a=0; b¹ 0, .
a=0; b=0, , ax = -b, , x .
: y = ax + b.
X0 Y0, , . . Y0 = aX0 + b.
1.1.
2x 3 + 4(x 1) = 5.
. , x: 2x 3 + 4x 4 = 5, 2x + 4x = 5 + 4 + 3,
6x = 12, x = 2.
: 2.
1.2.
2x 3 + 2(x 1) = 4(x 1) 7.
. 2x + 2x 4x = 3 +2 4 7, 0x = 6.
: Æ .
1.3. .
2x + 3 6(x 1) = 4(x 1) + 5.
. 2x 6x + 3 + 6 = 4 4x + 5,
4x + 9 = 9 4x,
-4x + 4x = 9 9,
0x = 0.
: .
a1x1 + a2x2 + + anxn = b,
a1, b1, ,an, b , n x1, x2, , xn.
, , , . n , :
2.4.
. , , - , .
: x= (8 3y) / 2.
y = 2. x = 1.
: (1; 2).
2.5.
. , ( x + y = 3, x + y = 3,5).
: .
2.6.
. , 2 (.. ).
: .
2.7.
. , .
2 , , 3y + 6z = 3. y 2z = 1. , 7y = 7, y = 1.
,
y = 1 , z = 0. y =1 z = 0 , x = 1.
: (1; 1; 0).
2.8. a
?
. x:
x = (a / 2)y + a / 2 +1.
,
(a + 1)( (a / 2)y + a / 2 +1) + 2ay = 2a + 4.
2 :
(a + 1)(a + 2 ay) + 4ay = 4a + 8,
4ay a(a + 1)y = 4(a + 2) (a + 1)(a + 2),
ya(4 a 1 ) = (a + 2)(4 a 1),
ya(3 a) = (a + 2)(3 a).
, , a = 3 0y = 0, .. y.
: 3.
ax2 + bx + c = 0, a, b c (a¹ 0);
x , .
ax2 + bx + c = 0 a .
x2 + (b / a)x + (c / a) = 0
x2 + (b / a) + (c / a) = (x2 + 2(b / 2a)x + (b / 2a)2) (b / 2a)2 + (c / a) =
= (x + (b / 2a))2 (b2) / (4a2) + (c / a) = (x + (b / 2a))2 ((b2 4ac) / (4a2)).
(b2 4ac) D.
x2 + (b / a)x + (c / a) = (x + (b / 2a))2 (D / (4a2)).
:
D / (4a2) = (Ö D)2 / (2a)2 = (Ö D / 2a)2,
x2 + (b / a)x + (c / a) = (x + (b / 2a))2 (Ö D / 2a)2.
:
x2 + (b / a)x + (c / a) = (x + (b / 2a) (Ö D / 2a))(x + (b / 2a) + (Ö D / 2a)) =
= (x (( -b + Ö D) / 2a)) (x (( b Ö D) / 2a)).
:
ax2 + bx + c = a(x x1)(x x2),
ax2 + bx + c = 0 X1 ¹ X2 X1 X2, X1 = X2 X1.
, , ,
x2 + (b / a)x + (c / a) = 0,
ax2 + bx + c = 0, :
X1=(-b + Ö D) / 2a; X2= (-b - Ö D) / 2a.
x2 + (b / a)x + (c / a) = (x x1)(x x2).
:
b2 4ac = D.
x2 + (b / a)x + (c / a) = (x + (b / 2a))2 (D / (4a2))
x2 + (b / a)x + (c / a) = (x + (b / 2a))2.
, D = 0 ax2 + bx + c = 0 2: X1 = b / 2a
3) D (D < 0), D > 0,
x2 + (b / a)x + (c / a) = (x + (b / 2a))2 (D / (4a2))
, , . ,
x2 + (b / a)x + (c / a) = 0
. ax2 + bx + c = 0.
,
D = b2 4ac.
D = 0, :
X=-b / (2a).
D > 0, :
X1=(-b + Ö D) / (2a); X2= (-b - Ö D) / (2a).
D < 0, .
b c , , :
ax2 + bx + c = 0
, x2 1, . :
x2 + px + q = 0.
x2 + (b / a)x + (c / a) = (x x1)(x x2),
X1 X2 ax2 + bx + c =0. .
x2 + (b / a)x + (c / a) = x2 x1x x2x + x1x2 = x2 (x1 + x2)x +x1x2.
, X1 + X2 = b / a X1X2 = c / a. , . (1540 1603):
1 (). X, c X2; , X2.
2 ().
X1 + X2 = b / a X1X2 = c / a,
X1 X2 ax2 + bx + c = 0.
. X1 + X2 = b / a X1X2 = c / a , ax2 + bx + c = 0 X1 2, X2 = X1. , D = 0 ax2 + bx +c = 0 .
, ,
(1 / X1) + (1/ X2)= ( X1 + X2)/ X1X2 ;
X12 + X22 = (X1 + X2)2 2 X1X2;
X1 / X2 + X2 / X1 = (X12 + X2 2) / X1X2 = ((X1 + X2)2 2X1X2) / X1X2;
X13 + X23 = (X1 + X2)(X12 X1X2 + X22) =
= (X1 + X2)((X1 + X2)2 3X1X2).
3.9. 2x2 + 5x 1 = 0.
. D = 25 42( 1) = 33 >0;
X1 = (- 5 + Ö 33) / 4; X2 = (- 5 -Ö 33) / 4.
: X1 = (- 5 + Ö 33) / 4; X2 = (- 5 -Ö 33) / 4.
3.10. x3 5x2 + 6x = 0
. x(x2 5x + 6) = 0,
x = 0 x2 5x + 6 = 0.
, X1 = 2 , X2 = 3.
: 0; 2; 3.
3.11.
x3 3x + 2 = 0.
. , 3x = x 2x, x3 x 2x + 2 = 0,
x(x2 1) 2(x 1) = 0,
(x 1)(x(x + 1) 2) = 0,
x 1 = 0, x1 = 1,
x2 + x 2 = 0, x2 = 2, x3 = 1.
: x1 = x3 = 1, x2 = 2.
3.12.
. x:
X + 2 ¹ 0; x 6 ¹ 0; 2x 7 ¹ 0 x ¹ 2; x ¹ 6; x ¹ 3,5.
(7x 14)(x2 7x + 12) = (14 4x)(x2 4x 12), .
7x3 49x2 + 84x 14x2 + 98x 168 + 4x3 16x2 48x 14x2 + 56x + 168 = 0,
11x3 93x2 + 190x = 0,
x(11x2 93x + 190) = 0,
x1 = 0
11x2 93x + 190 = 0,
.. x1 = 5; x2 = 38 / 11.
.
: x1 = 0; x2 = 5; x3 = 38 / 11.
3.13. x6 5x3 + 4 = 0
. y = x3,
y2 5y + 4 = 0, Y1 = 1; Y2 = 4.
,
: x3 = 1 x3 = 4, . . X1 = 1 X2 = 3Ö 4
: 1; 3Ö 4.
3.14. (x3 27) / (x 3) = 27
. ( ):
(x 3)(x2 + 3x + 9) / (x 3) = 27 . :
x2 + 3 x 18 = 0 X1 = 3; X2 = -6
(X1 ).
: -6
3.15.
(x2 + x 5) / x + (3x) / (x2 + x 5) = 4.
. y= (x2 + x 5) / x, y + 3 / y = 4.
: y + 3 / y 4 = 0, (y2 4y + 3) / y = 0,
y2 4y + 3 = 0 Y1 = 1; Y2 = 3 ( ).
, ()
(x2 + x 5) / x = 1 (x2 + x 5) / x = 3.
:
(x2 + x 5) / x 1 = 0 (x2 + x 5) / x 3 = 0;
X1 = Ö 5; X2 = Ö 5 X3 = 1 + Ö 6; X4 = 1 Ö 6
( ).
: Ö 5; Ö 5; 1 + Ö 6; 1 Ö 6 .
3.16. x(x + 2)(x + 3)(x + 5) = 72.
.
(x + 2)(x + 3)(x + 5)x = 72, (x2 + 5x + 6)(x2 + 5x) = 72.
y = x2 + 5x, (y + 6)y = 72,
y2 + 6y 72 = 0.
: Y1 = 6; Y2 = 12.
,
x2 + 5x = 6 x2 + 5x = 12.
X1 = 1; X2 = 6. , D = 26 48 = 23 < 0.
: 6; 1.
3.17. 4x2 + 12x + 12 / x + 4 / x2 = 47.
. : 4(x2 + 1 / (x2)) + 12(x + 1 / x) = 47.
y = x + 1 / x, ,
y2 = (x +1 / x)2 = x2 +2 + 1 / (x2),
x2 + 1 / (x2) = y2 2.
4(y2 2) + 12y = 47, 4y2 + 12y - 55 = 0.
Y1 = 5 / 2; Y2 = 11 / 2.
x + 1 / x = 5 / 2 x + 1 / x = 11 / 2.
:
x + 1 / x 5 /2 = 0 x + 1 / x + 11 / 2 = 0;
X1 = 2; X2 = 1 / 2 X3 = ( - 11 + Ö 105) / 4; X4 = ( -11 - Ö 105) / 4
( ).
: 2; 0,5; ( - 11 + Ö 105) / 4; (-11 - Ö 105) / 4.
3.18. x3 x2 9x 6 = 0.
. . ( )
± 1, ± 2, ± 3, ± 6.
, X = -2 .
x3 x2 9x 6 x + 2
x3 x2 9x 6 = (x + 2)(x2 3x 3) = 0.
x2 3x 3 = 0,
X2 = (3 - Ö 21) / 2, X3 = (3 + Ö 21) / 2.
: xÎ {-2; (3 - Ö 21) / 2; (3 + Ö 21) / 2}.
3.19.
x3 x2 8x + 6 = 0.
. an = 1, a0 = 6. , , 6: ± 1, ± 2, ± 3, ± 6. , x = 3, .. 27 9 24 + 6 = 0.
(x3 x2 8x + 6) (x 3)
: x3 x2 8x + 6 = (x 3)(x2 + 2x 2), .. (x 3)(x2 + 2x 2) = 0. , x1 = 3 , , x2,3 = 1 ± Ö 3 x2 + 2x 2 = 0.
: x1 = 3; x2,3 = 1 ± Ö 3.
3.20.
4x4 + 8x3 + x2 3x 1 = 0.
. an = 4, a0 = 1. : ± 1; ± 0,5; ± 0,25 ( 4 ± 1; ± 2; ± 4, ( 1) ± 1). x = +1, 4 + 8 + 1 3 1 ¹ 0; x = 0,5,
4 / 16 8 / 8 + 1 / 4 + 3 / 2 1 = 0, .. x = 0,5 .
(4x4 + 8x3 + x2 3x 1) (x + 0,5):
: (x + 0,5)(4x3 + 6x2 2x 2) = 0.
x1 = 0,5 (, ) 4x3 + 6x2 2x 2 = 0, .. 2x3 + 3x2 x 1 = 0. : x = 0,5. .
: (x + 0,5)(2x2 + 2x 2) = 0. x2 = 0,5 x3,4 = ( 1 ± Ö 5) / 2.
: x1 = x2 = 0,5; x3,4 = ( 1 ± Ö 5) / 2.
: , x = 0,5, , (x + 0,5). 2x3 + 3x2 x 1 = 0 :
2x3 + 3x2 x 1 = 2x3 + x2 +2x2 + x 2x 1 = 2x2(x + 0,5) + 2x(x + 0,5) 2(x+0,5) =
= (x +2)(2x2 + 2x 2) = 0.
x1 = 0,5; x3,4 = ( 1 ± Ö 5) / 2.
anxn + an 1 xn 1 + +a1x + a0 = 0
, , , ,
an 1 = ak, k = 0, 1, , n.
ax4 + bx3 + cx2 + bx + a = 0,
a, b c , a ¹ 0. :
a(x2 + 1 / x2) + b(x + 1 / x) + c = 0;
t2 = x2 + 2 + 1 / x2, x2 + 1 / x2 = t2 2;
:
at2 + bt + c 2a = 0;
.
x + 1 / x = t.
x= -1 , , x + 1, .
4.21. , ,
ax5 + bx4 + cx3 + cx2 + bx + a = 0
, x = 1 , x + 1. .
, . - . , 1 . . , , , , , .
P (x) = a0xn + a1xn 1 + + an
n X1, X2, , Xn.
a0xn + a1xn 1 + + an = a0(x x1)(x x2)(x xn).
a0 ¹ 0 .
Xn + (a1 / a0)xn 1 + + (an / a0) =
= xn (x1 + x2 + +xn)xn 1 + (x1x2 +x1x3 + +xn-1xn)xn 2 +
+ + (-1)nx1x2xn.
, . ,
x1 + x2 + + xn = -a1 / a0,
x1x2 + x1x3 + + xn 1xn = a2 / a0,
.
x1x2× × xn = (-1)nan / a0.
5.22. , x3 3x2 + 7x + 5 = 0.
. x1, x2 x3.
s 1 = x1 + x2 +x3 = 3,
s 2 = x1x2 + x1x3 + x2x3 = 7,
s 3 = x1x2x3 = 5.
y1, y2, y3, b1, b2, b3, y3 1. y1 = x12, y2 = x22, y3 = x32
b1 = (y1 + y2 + y3) = (x12 + x22 + x32),
b2 = y1y2 + y1y3 + y2y3 = x12x22 + x12x32 + x22x32,
b3 = y1y2y3 = x12x22x32 .
x12 + x22 + x32 = (x1 + x2 +x3)2 2(x1x2 + x1x3 + x2x3) = s 12 - 2s 2 = 32 2× 7 = 5,
x12x22 + x12x32 + x22x32 = (x1x2 + x1x3 + x2x3)2 2x1x2x3(x1 + x2 +x3)= s 22 2s 1s 3 = = 72 2× 3× ( 5)= 79,
x12x22x32 = (x1x2x3)2 = s 32 = 25.
, b1 = 5, b2 = 79, b3 = 25,
y3 + 5y2 + 79y 25 = 0.
: y3 + 5y2 + 79y 25 = 0.
.
.
6.23. (x; y) , (x + y) . .
. y = 7 2x. y ,
2x2 + 7x 6 = 0 X1 = 2; X2 = 3 / 2. Y1 = 3; Y2 = 4.
(2; 3) (1,5; 4). x + y = 1,5 + 4 = 5,5.
: 5,5.
6.24.
. a = x + y; b = xy.
x y,
:
y2 3y + 2 = 0,Y1 = 1; X1 = 2; Y2 = 2; X2 = 1.
: (2; 1) , (1; 2).
6.25.
. :
(x ¹ 0) x y = 3 / x, .. y x = 3 / x, ,
y ,
- 3x2 = 3, X1 = 1; X2 = 1, Y1 = 4; Y2 = 4.
: (1; 4), ( 1; 4).
6.26. .
. , 16 , 15 2.
. . 2 + 2 = 16, .. + = 8 = 15
,
.. , .
, = 8 . , (8 - ) = 15, .. 8 - 2 = 15
2 - 8 + 15 = 0.
: D = (- 8)2 - 4× 1× 15 = 64 - 60 = 4,
1,2 = (8 ± Ö 4) / 2 = (8 ± 2) / 2.
, 1 = 5, 2 = 3. = 8 - , 1 = 3, 2 = 5. , 3 5 .
: 2 - 8 + 15 = 0 , , : 8, 15, z2 - 8z + 15 = 0.
, . - , . . , , .
6.27.
. , = 11 - 2. , : 2 + (11 - 2)2 = 53.
:
2 + 121 - 44 + 42 = 53
52 - 44 + 68 = 0. ,
52 - 44 + 68 = 0.
, D = (- 44)2 - 4× 5× 68 = 1936 - 1360 = 576,
1,2 = (44 ± 24) / 10.
1 = 6,8; 2 = 2, Þ 1 = 11 - 2× 6,8 = - 2,6; 2 = 11 - 2× 2 = 7.
: 1 = 6,8; 1 = - 2,6; 2 = 2; 2 = 7.
( = 2 = + 1 / ). .
7.28. 12 / (2 + 2) - 3 / (2 + 2 - 2) = 1.
. , , . , , 2 + 2. , , = 2 + 2.
12 / - 3 / ( - 2) = 1 (2 - 11 + 24) / (( - 2)) = 0,
y1 = 3; y2 = 8. 2 + 2 = 3 ( 1 = 1, 2 = - 3) 2 + 2 = 8 ( 3 = 2, 4 = - 4).
, , ( ).
7.29.
. 1 / U, 1 / V.
.. U V. U V: U = 4 - 3V / 2, : 5(4 - 3V / 2) - 2V = 1, V = 2. U = 1 1 / x = 1, 1 / y = 2.
: x = 1, y = 0,5.
7.30.
(x 4)(x 5)(x 6)(x 7) = 1680.
. (x 4)(x 7)× (x 5)(x 6) = 1680, ..
(x2 11x + 28)(x2 11x + 30) = 1680.
x2 11x + 28 = t, t(t + 2) = 1680, t2 + 2t 1680 = 0, t1 = 42; t2 = 40.
x2 11x + 28 = 42; x2 11x + 70 = 0; D = 121 280 < 0 Þ x1,2 Î Æ .
x2 11x + 28 = 40; x2 11x 12 = 0; x1 = 12; x2 = 1.
: x1 = 12; x2 = 1.
7.31.
2x4 + 3x3 16x2 + 3x + 2 = 0.
. . x2 ¹ 0,
2x2 + 3x 16 +3 / x + 2 / x2 = 0, ..
2(x2 + 1 / x2) + 3(x + 1 / x) 16 = 0,
x + 1 / x = t, x2 + 2 + 1 / x2 = t2, .. x2 + 1 / x2 = t2 2, 2(t2 2) + 3t 16=0, .. 2t2 + 3t 20 = 0, t1 = 4; t2 = 5 / 2 = 2,5. ,
x + 1 / x = 4; x2 + 4x + 1 = 0; x1,2 = 2 ± Ö 3,
x + 1 / x = 2,5; 2x2 5x + 2 = 0; x3 = 2; x4 = 1 / 2.
: x1,2 = 2 ± Ö 3; x3 = 2; x4 = 1 / 2.
7.32.
(x + 3)4 + (x + 5)4 = 16.
. x = t 4. (t 1)4 + (t + 1)4 = 16, ..
t4 4t3 + 6t2 4t + 1 + t4 + 4t3 + 6t2 + 4t + 1 = 16,
.. 2t4 + 12t2 14 = 0, t4 + 6t2 7 = 0. t2 = z ³ 0,
z2 +6z 7 = 0, z1 = 7; z2 = 1.
t2 = z ³ 0 z1. , z = 1, .. t2 = 1, t1 = 1; t2 = 1. , x1 = 1 4 = 5 x2 = 1 4 = 3.
: x1 = 5 x2 = 3.
7.33.
13x / (2x2 + x +3) + 2x / (2x2 5x + 3) = 6.
. x ¹ 0:
13 / (2x + 1 + 3 / x) + 2 / (2x 5 +3 / x) = 6,
2x + 3 /x = t. 13 / (t + 1) + 2 / (t 5) = 6, ..
13t 65 + 2t + 2 = 6t2 24t 30, ..
6t2 39t + 33 = 0, .. 2t2 13t + 11 = 0,
t1 = 1; t2 = 5,5.
:
2x + 3 / x = 1; 2x2 x + 3 = 0; D = 1 24 < 0 Þ x Î Æ .
2x + 3 / x = 5,5; 4x2 11x + 6 = 0; x1 = 2; x2 = 0,75.
: x1 = 2; x2 = 0,75.
7.34.
x4 2x3 + x 0,75 = 0.
. , x2:
x4 2x3 + x2 x2 + x 0,75 = 0, ..
(x2 x)2 (x2 x) 0,75 = 0.
x2 x = t, t2 t 0,75 = 0, x1 = 0,5; x2 = 1,5.
, :
x2 x = 0,5; x2 x + 0,5 = 0; D = 1 2 < 0 Þ x Î Æ .
x2 x = 1,5; x2 x 1,5 = 0; x1,2 = (1 ± Ö 7) / 2.
: x1,2 = (1 ± Ö 7) / 2.
7.35.
x2 + 81x2 / (9 + x)2 = 40.
. : a2 + b2 = (a b)2 + 2ab ((a - b)2 = a2 - 2ab + b2Þ Þ a2 + b2 = (a - b)2 + 2ab). :
(x 9x / (9 + x))2 + 2x× 9x / (9 + x) = 40,
(x2 / (9 + x))2 + 18x2 / (9 + x) = 40.
: (x2 / (9 + x)) = t. t2 + 18t 40 = 0, t1 = 20; t2 = 2. :
(x2 / (9 + x)) = 2; x2 2x 18 = 0; x1,2 = 1 ± Ö 19,
(x2 / (9 + x)) = 20; x2 + 20x + 180 = 0; D = 400 720 < 0, Þ x Î Æ .
: x1,2 = 1 ± Ö 19.
8.36.
. , ¹ 0. , , = 0, = 0, = 0 = 0 . 2.
82 / 2 - 6 / 2 + 2 / 2 = 0 82 / 2 - 6 / + 1 = 0.
U = / .
8U2 - 6U + 1 = 0.
, U1 = 0,5; U2 = 0,25. , x / y = 1 / 2, x / y = 1 / 4. =2 = 4 ( ) . 52 = 5, 1 = 1, 2 = - 1; 1 = 2, 2 = - 2. 172 = 5, 3 = Ö (5 / 17), x4 = - Ö (5 / 17); y3 = 4Ö (5 / 17), y4 = - 4Ö (5 /17).
x / y , , (8x2, 6xy, y2), . y2 x / y.
x y , k, k.
P (x, y) = 0 k x y, P (x, y) k. x y yk ( y = 0 ) x / y. .
8.37.
. . 7 , 3, 7y2 - 10xy + 3x2 = 0, . x2 7U2 - 10U + 3 = 0 ( U = y / x, , x ¹ 0). , y = x y = 3x / 7. , , :
x1 = 7, y1 = 3; x2 = - 7, y2 = - 3.
: x1 = 7, y1 = 3; x2 = - 7, y2 = - 3.
. x y, . , , .
8.38. (x - 1)4 + 9(x + 1)4 = 10(x2 - 1)2.
. , . : U V:
U = (x - 1)2, V = (x + 1)2.
U2 + 9V2 = 10UV.
, V2 W:
W = U / V = (x - 1)2 / (x + 1)2.
W2 - 10W + 9 = 0.
W1 = 1, W2 = 9.
(x - 1)2 / (x + 1)2 = 1 (x - 1)2 / (x + 1)2 = 9.
, (x - 1) / (x + 1) = 1, (x - 1) / (x + 1) = - 1.
, (x - 1) / (x + 1) = 3, (x - 1) / (x + 1) = - 3. , , , x1 = 0, x2 = - 2, x3 = - 0,5.
: x1 = 0, x2 = - 2, x3 = - 0,5.
8.39.
3(x2 x + 1)2 5(x + 1)(x2 x + 1) 2(x + 1)2 = 0.
. , ..
ay2a + bya za + cz2a = 0,
a, b, c, a , ; y = y(x), z = z(x) x. (x2 x + 1)2 ¹ 0:
3 5(x + 1) / (x2 x + 1) 2((x + 1) / (x2 x + 1))2 = 0.
(x + 1) / (x2 x + 1) = t, 3 5t 2t2 = 0, .. t1 = 3; t2 = 0,5. :
(x + 1) / (x2 x + 1) = 0,5 = 1 / 2; 2x + 2 = x2 x + 1; x2 3x 1 = 0; x1,2 = (3 ± Ö 13) / 2,
(x + 1) / (x2 x + 1) = 3; x + 1 = 3x2 + 3x 3; 3x2 2x + 4 = 0; D = 4 48 < 0, Þ x Î Æ .
: x1,2 = (3 ± Ö 13) / 2.
, P (x, y) , P (x , y) = P (y, x).
P1 (x, y) P2 (x, y) , : x + y = U, xy = V. , P (x, y) U V.
9.40.
. , :
x2 + xy + y2 = x2 + 2xy + y2 - xy = (x + y)2 - xy.
: x + y = U, xy =V. :
, U2 + U - 72 = 0 U1 = 8,U2 = - 9. V1 = 15, V2 = 32. :
: x1 = 3, y1 = 5; x2 = 5, y2 = 3.
9.41.
. X Y:
X = 1 / x, Y = 1 / y,
U V: U = X + Y = 1 / x + 1 / y, V = XY = 1 / xy.
:
U = 5, V = 6.
X1 = 2, Y1 = 3; X2 = 3, Y2 = 2, x1 = 1 / 2, y1 = 1 / 3; x2 = 1 /3, y2 = 1 / 2. U = x + y, V = xy,
.
: x1 = 1 / 2, y1 = 1 / 3; x2 = 1 /3, y2 = 1 / 2.
, . . , , .. ( ).
, ax + b = c x a, b, c. a ¹ 0 x = (c - b) / a. a = 0, b = c, b = c, . b ¹ c, a = 0, .
, . , :
:
: - , - , .
10.42. px = 6 x p. p ¹ 0, p, x = 6 /p. p = 0, , 0× x = 0 x.
: p ¹ 0 x = 6 / p; p = 0 .
10.43. : - a 3a.
. :
a < 0, - a > 3a;
a = 0, - a = 3a;
a > 0, - a < 3a.
10.44. ax = 1.
. : x = 1 / a. a = 0 , :
: a = 0, ; a ¹ 0, x = 1 / a.
10.45. (a2 - 1)x = a + 1.
. , :
. . , . . .
. ,
: a = - 1, x ; a = 1, ; a ¹ ± 1, x = 1 / (a - 1).
10.46. a ax2 - x + 3 = 0 ?
. : . , . , , , a = 0, . a ¹ 0, . 1 - 12a , , a = 1 / 12.
: a = 0 a = 1 / 12.
10.47. a (a - 2)x2 + (4 - 2a)x + 3 = 0 ?
. , a = 2. a = 2 . a ¹ 2, , , , . a = 2 a = 5. , a = 2 ,
: a = 5.
, ( , ). , , , . , .
10.48. a ax2 + 4x + a + 3 = 0 ?
. a = 0 , . a¹ 0 , , , 16 - 4a2 - 12a . - 4 < a < 1. (- 4; 1) 0, , , .
: - 4 < a < 0 0 < a < 1.
10.49. a a(a + 3)x2 + (2a + 6)x - 3a - 9 = 0 ?
. a = 0 a = - 3. a = 0 . , a = - 3 . a = - 3 . a ¹ - 3 a ¹ 0, a + 3, ax2 + 2x - 3 = 0, 4(1 + 3a) a > - 1 / 3. , (- 1 / 3; ¥ ) a = 0, a = - 3.
: a = - 3 - 1 / 3 < a < 0, a > 0.
10.50. a (x2 - ax + 1) / (x + 3) = 0 ?
.
, . x ¹ - 3 . , ! - 3. D = a2 - 4, D = 0, a = ± 2; x = - 3 x2 - ax + 1 = 0 a = - 10 / 3, a - 3.
: a = ± 2 a = - 10 / 3.
10.51. a ax2 = a2
| x - 3| ³ a?
. a ¹ 0 , . a = 0, , . , a = 0.
: a = 0.
10.52.
(a2 - 9)x = a2 + 2a - 3.
. . :
(a - 3)(a + 3)x = (a + 3)(a - 1).
a = - 3, : 0x = 0. , x Î R, .. . a ¹ - 3, : (a - 3)x = a - 1. a = 3 0x = 2. . a ¹ - 3 x = (a - 1) / (a - 3). (, x = 3 a = 4, x = 3 / 5 a= - 2 ..)
: a = - 3, x Î R; a = 3, x Î Æ ; a ¹ ± 3, x = (a - 1) / (a - 3).
10.53.
(x - 4) / (x + 1) - 1 / a(x + 1) = - 2 / a.
. , (x + 1)a ¹ 0, .. x ¹ - 1, a ¹ 0. , a(x + 1) ¹ 0:
(x - 4)a - 1 = - 2(x + 1), .. (a + 2)x = 4a - 1.
a = - 2, 0 = - 9. , xÎ Æ . a ¹ - 2, x = (4a +1) / (a + 2). , , x ¹ - 1. , a x - 1.
(4a - 1) / (a + 2) = - 1, .. 4a - 1 = - a - 2, .. 5a = - 1, a= - 1 / 5.
, a ¹ 0, a ¹ - 2, a ¹ - 1 / 5 (4a - 1) / (a + 2).
: x Î Æ a Î {- 2, 0, - 1 / 5}; x = (4a - 1) / (a + 2) aÏ {- 2, 0, - 1 / 5}.
10.54.
(a - 5)x2 + 3ax - (a - 5) = 0.
. (a - 5) = 0, .. a = 5 15x - 0 = 0, .. x = 0. a - 5 ¹ 0, .. a ¹ 5
X1,2 = (- 3a ± Ö (9a2 + 4(a - 5)2)) / (2(a - 5)).
: x = 0 a = 5; x = (- 3a ± Ö (9a2 + 4(a - 5)2)) / (2(a - 5)) a ¹ 5.
10.55.
1 / (x - 1) + 1 / (x - a) = (a + 1) / a.
. , a(x - 1)(x - a) ¹ 0, .. x ¹ 1, x ¹ a, a ¹ 0.
(a + 1)x2 - (a2 + 4a + 1)x + (2a2 + 2a) = 0.
a +1 = 0, .. a = - 1, , 2x = 0, .. x = 0.
a + 1 ¹ 0, .. a ¹ - 1, ,
x1,2 = (a2 + 4a + 1 ± Ö (a4 + 2a2 + 1)) / (2(a +1) = (a2 + 4a + 1 ± (a2 + 1) ) / (2(a + 1))
.. x1 = a + 1, x2 = 2a / (a + 1). a, x = 1 x = a, .
a + 1 = 1 Þ a = 0 ;
a + 1 = a Þ 1 = 0 ;
2 / (a + 1) = 1 Þ 2a = a + 1, .. a = 1;
2 / (a + 1) = a Þ 2a = a2 + a, a = 1 a = 0 .
, a ¹ - 1, a ¹ 0, a ¹ 1, x1 = a + 1, x2 = 2a / (a + 1).
, a = 1. : x1 = 1 x2 = 2, x1 = 1 .
: x1 = a + 1 x2 = 2 a ¹ 0, a ¹ ± 1; x = 0 a = - 1; x = 2 a = 1.
10.56. a
?
. a .
a = 1, - 3y + 0,5 = 0, .. y = 1 /6. , x. .
y = ((1 - a)x + 1,5 - a) / (2a + 1),
:
x + ((2 - 2a)x + 3 - 2a) / (2a + 1) + ((1 - a)x2 + 1,5x - ax) / (2a + 1) +1 = 0, ..
2ax + 3x - 2ax + 3 - 2a + x2 - ax2 +1,5x - ax + 2a + 1 = 0,
(1 - a)x2 + (4,5 - a)x + 4 = 0.
, :
(9 / 2 - a)2 - 4× 4(1 - a) = 0, .. a2 + 7a + 17 / 4 = 0, .. a = (- 7 ± 4Ö 2) / 2.
: a = 1, a = - 1 / 2, a = (- 7 ± 4Ö 2) / 2.
10.57.
x3 (a + b + c)x2 + (ab + ac + bc)x abc =0.
. x3 ax2 bx2 cx2 + abx + acx +bcx abc = 0,
: x2(x a) bx(x a) cx(x a) cx(x a) + bc(x a),
(x a)(x2 bc cx + bc).
(x a) = 0,
x1 = a.
x2 bc cx + bc = 0,
x(x b) c(x b) = 0,
(x b)(x c) = 0,
x b = 0, x2 = b
x c = 0, x3 = c.
: x1 = a; x2 = b; x3 = c.
: , :
x3 + px2 + qx + r = 0,
x1 + x2 + x3 = - p,
x1x2 + x1x3 + x2x3 = q,
x1x2x3 = - r .
:
x1 + x2 + x3 = a + b + c,
x1x2 + x1x3 + x2x3 = ab + bc +cd,
x1x2x3 = abc.
, x1 = a; x2 = b; x3 = c.
. . :
:
x2 + y2 - 2ax - 2by + c = 0.
11.58. :
. , :
x2 + y2 - 2x + 4y - 20 = (x2 - 2x +1) + (y2 + 4y + 4) - 1 - 4 - 20 = (x - 1)2 + (y + 2)2 - 25.
, :
A(1; - 2) 5. 2x - y = - 1 , B(0; 1) C(2; 5). 5 A B C. M(1; 3) N(- 3; - 5). : x1 = 1, y1 = 3; x2 = - 3, y2 = - 5.
, , , : | a| = | b| , a = b, a = - b.
| 3x - 1| = | 2x + 3| .
, 3 - 1 = 2 + 3, 3 - 1 = - (2 + 3). 4, - 2 / 5. , 1 = 4, 2 = - 2 / 5.
, , . , ( ). .
. ,
f (x), f (x) ³ 0,
| f (x) | = f (x), f (x) < 0.
12.59. .
| x| = | 3 - 2x| - x - 1.
. x x = 0, 3 - 2x x = 3 / 2. 0 3 / 2 (- ¥ ; 0),[0; 3 / 2], (3 / 2; ¥ ). - ¥ < x < 0 x < 0 3 - 2x > 0. | x| = - x, | 3 - 2x| = 3 - 2x - x = 3 - 2x - x - 1. , , x = 1. x (- ¥ ; 0), . 0 £ x £ 3/ 2 x ³ 0, 3 - 2x ³ 0, | x| = x, | 3 - 2x| = 3 - 2x. x = 3 - 2x - x - 1. , x = 0,5. x [0; 3 / 2], 1 / 2 . , (3 / 2; +¥ ) x > 0, 3 - 2x < 0, | x| = x, | 3 - 2x| = - (3 - 2x) x = - (3 - 2x) - x - 1, .. 0 = - 4. , .
, , , x = 0,5.
: x = 0,5.
.
12.60. | 8 - 5x| = | 3 + x| + | 5 - 6x| .
(8 - 5x), (3 + x) (5 - 6x) 8 /5, - 3, 5 / 6. 4 . , , , (- ¥ ; - 3), (5 / 6; 8 /5], (8 / 5; +¥ ) , [- 3; 5 / 6] 8 - 5x = 3 + x + 5 - 6x. [- 3; 5 / 6].
: [- 3; 5/ 6].
, . .
12.61. | 2x - 3 - | x + 2| | = 8x + 12.
. (x + 2) x = - 2. x < - 2, (x + 2) < 0 | x + 2| = - (x + 2). , (- ¥ ; - 2) | 2x - 3 + (x + 2)| = 8x + 12, .. | 3x - 1| = 8x + 12. x < - 2 3x - 1 < 0 | 3x - 1| = - (3x - 1). - (3x - 1) = 8x + 12, x = - 1. (- ¥ ; - 2), .
x ³ - 2. | x + 2| = x + 2, | 2x - 3 - (x + 2)| =8x + 12, .. | x - 5| = 8x + 12. : x < 5 x ³ 5. ½ x - 5| = - ( - 5), - (x - 5) = 8x + 12. - 7 / 9. - 2 £ (- 7 / 9) £ 5, - 7 / 9 . x ³ 5, | x - 5| = x - 5 x - 5 = 8x + 12. - 17 / 7. [5; +¥ ), . , x = - 7 / 9.
: x = - 7 / 9.
12.62.
| 1 2x| + | 3x + 2| + | x| = 5.
. , , , :
) x < 2 / 3, 1 2x > 0, 3x + 2 < 0, x < 0 :
1 2x 3x 2 x = 5, .. 6x = 6, x = 1 Î (¥ ; 2 / 3).
) 2 / 3 £ x < 0, 1 2x > 0, 3x + 2 ³ 0, x < 0 :
1 2x + 3x + 2 x = 5, .. 3 ¹ 5, [ 2 / 3; 0) .
) 0 £ x < 0,5, : 1 2x + 3x + 2 + x = 5, .. 2x = 2; x = 1 Ï [0; 0,5).
) 0,5 £ x, 1 +2x + 3x + 2 + x = 5, 6x = 4, x = 2 / 3 Î (0,5; ¥ ).
: x1 = 1; x2 = 2 / 3.
12.63.
| x | + | x 1 | = 1.
. (x 1) = 0, x = 1; Þ :
A) x Î (- ¥ ; 0), x x +1 = 1; 2x = 0; x = 0 Ï (- ¥ ; 0).
) x Î [0; 1), x x +1 = 1; 1 = 1 Þ x [0; 1).
) x Î [1; ¥ ), x + x 1 = 1; 2x = 2; x = 1 Î [1; ¥ ).
: x Î [0; 1].
1) : , . ax2 + bx + c = 0
: x1 + x2 = b / a; x1x2 = c / a.
2) : , ( ) , , . .
3) : , , . . ,
(x2 + x 5) / x + 3x / (x2 + x 5) + 4 = 0,
(x2 + x 5) / x = t, t + (3 / t) + 4 = 0.
: 21 / (x2 4x + 10) x2 + 4x = 6. x2 4 = t. 21 / (t + 10) - t = 6 ..
. ,
(x2 + 2x)2 (x +1)2 = 55.
, (x2 + 2x)2 (x2 + 2x + 1) = 55, x2 + 2x=t.
t2 t 56 = 0, t1 = 7, t2 = 8. x2 + 2x = 7 x2 + 2x = 8.
.
x = t (a + b) / 2.
4) : anxn + an 1xn 1 + + a1x + a0 = 0 p / q, p a0, q an, p q , pÎ Z, qÎ N.
5) , .. , , - , , - ..
6) : . ,
f (x), f (x) ³ 0,
| f (x) | = f (x), f (x) < 0.
¦ (c ) ¾ ().
¦ (c ) < 0 (¦ (c ) > 0) (1)
¾ () ¦ , (1) . () ¦ , (1) , .
¦ (c ) £ 0(¦ (c ) ³ 0) (2)
(1) ¦ (c ) = 0.
, .
, , ¦ (c ).
(1) (2), ¦ i(c ), . ¾ ¦ i(c ), .
, , .
.
, .
, 3 > 6 2 > 0 Î [2; +¥ ]. .
> 0 2 > 0 , Î [0; +¥ ], Î [-¥ ; 0]È [0; +¥ ]. .
, . .
1. , , , .
. () > Q(x) , () , , Î R.
. () > Q(x) () + () > Q(x) + T(x) .
. ) = () > Q(a) , .. = () > Q(x), () () =.
() + () > Q(a) + T(a) .
, = () + () > Q(x) + T(x). , = , .
) = b () + () > Q(x) + T(x), .. P(b) + T(b) > Q(b) + T(b) . P(b) > Q(b) . , = b P(x) > Q(x).
P(x) > Q(x) P(x) + T(x) > > Q(x) + T(x) , .
2. , Î R, , , .
. P(x) + T(x) > Q(x) , () , Î R.
. P(x) + T(x) > Q(x) P(x) > Q(x) T(x) .
. 1 P(x) + T(x) > Q(x) (-()), Î R; :
P(x) + T(x) T(x) > Q(x) T(x), P(x) > Q(x) T(x).
3. , , , .
. P(x) > Q(x) (1),
T(x) > 0, xÎ R,
P(x)× T(x) > Q(x)× T(x) (2).
. (1) (2) .
. = P(a) > Q(a) , .. = . T(a) () = () > 0.
P(a)× T(a) > Q(a)× T(a) , .. = . , = , = .
= b P(b)× T(b) > Q(b)× T(b) , .. = b .
P(b) > Q(b) , T(b) > 0. , = b .
, .
4. , , , , .
3 .
( )
ax + b > 0, ax + b < 0, ax + b ³ 0, ax + b £ 0, a ¹ 0,
:
a > 0
xÎ (-b/a ; ¥ ), xÎ ( -¥ ; -b/a ), xÎ [ -b/a ; ¥ ), xÎ ( -¥ ; -b/a],
< 0
xÎ ( -¥ ; -b/a), xÎ ( -b/a ; ¥ ), xÎ ( -¥ ; -b/a], xÎ [ -b/a ; ¥ ).
( )
ax2 + bx + c > 0,ax2 + bx + c < 0,
ax2 + bx + c ³ 0,ax2 + bx + c £ 0,
a, b, c ¾ ¹ 0.
ax2 + bx + c > 0 a, b c :
> 0 D = b2 4ac ³ 0
xÎ ( -¥ ;
)È
(
; ¥
);
> 0 D < 0 x ¾ ;
< 0 D ³ 0
xÎ (
;
);
< 0 D < 0
x = Æ (. . ).
ax2 + bx + c < 0 , (-1).
n(x) ¾ n- , c1, c2, ¼ , ci ¾ k1, k2, ¼ , ki , 1 > c2 > ¼ > ci. Pn(x)
n(x) = (x - c1) k1(x - c2) k2 ¼ (x ci)ki Qm(x),(3)
Qm(x) , Î R. , Qm(x) > 0. > c1 (3) n() > 0. 1 ¾ (k1 ¾ ), Î (2; 1) (3), , n()<0. , n() 1. 1 ¾ (k1 ¾ ), ( ) Î (2; 1) , , n() > 0 Î (c2; 1). , n() 1.
, (3), , 2 n() , k2 ¾ , , k2 ¾ . .
n() > 0,(4)
n() n() , .
:
4 + 33 4 > 0.(*)
. 4(), (*). ,
4() = (3 + 32 4).
, , = 1. ,
3 + 32 4 = (-1)(2 + 4 + 4) = (-1)( + 2) 2.
, 4() = ( - 1)( + 2) 2 (*)
( 1)( + 2)2 > 0. (**)
(**) . > 1 , , .
. = 1 4() , = 1 ¾ ( 1); = 0 , = 0 ¾ ; = -2 , = -2 ¾ 2. 4 () 1. , .
. Î (-¥ ; -2) È (-2; 0) È (1; ¥ ).
:
(2 3 2)(2 3 + 1) < 10.
: 2 3 2 = y. y(y +3) < 10, y2 + 3y 10 < 0, (y + 5)(y 2) < 0. 5<y<2. ,
, (-1; 4).
: (-1; 4).
:
4 342 + 225 < 0.
. 4 342 + 225 < 0. 2 = z, z2 34z + 225 = 0, : z1 = 9 z2 = 25. 2 = 9 2 = 25, 4 : -3, 3, -5, 5. , 4 342 + 225 = ( + 5)( + 3)( 3)( 5), :
( + 5)( + 3)( 3)( 5) < 0.
5, -3, 3, 5 . (-5; -3) (3; 5).
: (-5; -3)È (3; 5).
:
4 3 < 2(22 2).
. . .
4 43 + 22 + 4 3 < 0.
4 43 + 22 + 4 3 = 0, 1 = -1, 2,3 = 1, 4 = 3.
( 1) 2( + 1)( 3) < 0.
, , , . ( ), , . , (-1; 1) (1; 3).
, 1, 1, 3 .
: (-1; 1)È (1; 3).
(5)
n() Qm() ¾ , (4) : (5) [Qm(x)]2, (.. , Qm(x) ¹ 0),
n() × Qm(x) > 0,
(5).
-
a, b, c, d, k ¾ ¹ 0, ( = 0, - , (6) ). - (6), > <, ³ , £ . - . (6) ( + d)2, Î R x ¹ -d/c.
:
: 1, (5).
2(2 2) < 0.
: Î ( -1;0)È (0;2).
: Î (-1;0)È (0;2).
:
: ,
, , : [-4; -3)È (-1; 1].
: [-4; -3)È (-1; 1].
: :
: ¹ 0 ¹ 3, , = 0 , = 3 . , (, ). , ¹ 0 ¹ 3:
.
, , = 0 = 3. , = 0 , , . = 3 , ; , . , : (-¥ ; -4)È [1; 3)È È (3; 4,5]U0.
: (-¥ ; -4)È [1; 3)È (3; 4,5]U0.
:
. ,
, , 5, 1, 2, 6. (-¥ ; -5), (-5; 1), (1; 2), (2; 6),(6; +¥ ). , : (-5; 1) (2; 6). (-5; 1) 0, . , (-5; 0)È (0; 1)È (2; 6).
: (-5; 0)È (0; 1)È (2; 6).
:
. ,
0, 1, 2, 5, , . .
.
, : (-¥ ; 0), (0; 1), (2; 5).
: (-¥ ; 0)È (0; 1)È (2; 5).
, , , , , : , , .
:
½ 2 - 2½ + < 0.(*)
: 2 2, .
2 2 ³ 0,
(*)
2 + 2 < 0.
2 2 ³ 0 ( 1): Î (-2; - ].
2) , 2 2 < 0, ½ 2 - 2½ = 2 2, (*)
2 2 + < 0.
2 2 < 0 (. 2): Î (- ; -1).
, Î (-2; -1)
: Î (-2; -1).
. . ,
½ - 2½ < -.
y1 =½ 2 - 2½ y2 = -, , , y1<y2.
. 3 .
, , , ½ ½ 2= 2.
:
.(*)
: ¹ -2
½ - 1½ > ½ + 2½ . (**)
(**) ,
6 < -3,
.. < -1/2.
, ¹ -2, , (*) Î (-¥ ; -2)È (-2; -1/2).
: (-¥ ; -2)È (-2; -1/2).
: , :
: ½ +1½ ³ 0 , , ½ +1½ ¹ 0, : 2 + 5 > ½ +1½ . , (2 + 5) < + 1 < 2 + 5,
, 0. , ¹ -1, .
: 0.
: :
: ½ ½ = y. , ½ ½ + 1 > 0. : -2 ³ (y 2)(y + 1), y2 y £ 0, 0 £ y£ 1, 0 £ ½ ½ £ 1. -1£ £ 1.
: [-1; 1].
:
½ 2 3 + 2½ + ½ 2 + 1½ £ 5.
. 2 3 + 2 1 < x < 2 , 2 + 1 = -. , .
:
£
£ 2.
: .
½ ½ 3 + - 3½ - 5½ £ 3 + 8.
. .
. , .
:
a > 1/x.
:
:
ax2 1 > 0,ax2 1 < 0,
x > 0; x < 0.
. :
ax2 > 1.
> 0 2 > 1/a, < -1/ x > 1/ . : Î (1/ ; ¥ ). £ 0 2 1 > 0 , , .
. > 0 2 1<0 Î (-1/ ; 1/ ), ¾ Î (-1/ ; 0). a£ 0 2 1 < 0
, .. Î R , , Î (-¥ ; 0).
.
> 0 £ 0 , . .
.
: £ 0, Î (-¥ ; 0); > 0, Î (-1/ ; 0)È (1/ ; ¥ ).
: :
: : 3m2 + 3 2mx2 6 < m + 9x; mx2 9x < m + 3; (m 3)(m + 3)x < m + 3. m:
:
434 + 422 + 32 + + 8 ³ 0.
. , . 4 3. , y = ax, 2. = 0 ³ - . , > 0. y = ax,
4y4 + 4ay2 + 32y + a2 + 8a ³ 0.
:
a2 + (4y2 + 8)a + 4y2 + 32y ³ 0,
D = (2y2 + 4) 2 4y2 32y = 16(y 1) 2.
,
( + 2y2 + 4y)(a + 2y2 4y + 8) ³ 0,
(2y2 + 4y + a)(2y2 4y + 8 + a) ³ 0.
y, > 0. 2y2 + 4y + a ³ 0, , 0 < a < 2, y £ (-2 - ) y ³ (-2+ ); ³ 2, y . , .
: = 0, ³ - ; 0 < a < 2, £ 1/2a*(-2 - ) ³ 1/2a(-2 + ); ³ 2, .
:
: 1 £ £ 2, ( ¹ 0) f(x) = 2 2( + 1) + 1 [1; 2].
D = ( + 1) 2 ( 1) = 3 + 1, f(1) = -3, f(2) = 5.
4 ( ).
. = 0.
: < 5, ; ³ 5, 1/( + 1 + ) £ £ 2.
:
½ 22 + - 8½ £ 2 + 2 2 4.
: , ½ ½ £ b b £ a £ b.
£ -2 + + 4,
£ 2 + 4.
(; ) , . = a = a , . (2; 2), (-2; -2) (-0,5; -4,25) = 2 + 4.
: > 2, .
2 < a £ 2,
.
(
= 2 + 4 2 4 + = 0).
4 £ a £ -2, , , .
, . , .
, . .
:
( 1)( 5)( 7) < 0.
(. 1), , (2) : (-¥ , 1) (5, 7).
(. 2), , (3) : (2, 3) (4, +¥ ).
(2) (3). . , (2) (3) (5, 7) (. 3).
, (1) (5, 7).
:
2 6 + 10 < 0.
, ,
2 6 + 10 = 2 - 2× × 3 + 32 - 32 + 10 = ( 3) 2 +1.
(2)
( 3) 2+ 1 < 0,
, .
: (1) .
:
;
(. 4) : < -2; 0 < x < 2.
. x2 - 64 < 0, ( 8)( + 8) < 0. (. 5) : -8 < x < 8.
(. 6), , ( ): -8 < x < -2; 0 < x < 2. .
:
:
3( 10)( + 10) ³ 0, ( 10)( + 10) ³ 0
(.. ); (. 7) : -10 £ £ 0, ³ 10.
;
(. 8) £ -9; 3 < x < 15.
, (. 9) £ 0; > 3.
: :
:
, y < 2, 75, , 1 < y < 2,75. 2. y = 2
1 < x < 0,5. 0.
: = 0, y =2.
.
: f(x) > g(x), f(x) g(x) , .
y = f(x) = g(x).
, =g(x), f(x)>g(x). 1 2.
f(x,y)>0
, . .
1.
x + > 0.
. > -. = -. , , ( 3 ).
2.
2 > 0.
. < x2 .
= 2 () ( 4).
, ( ).
.
3.
. ( 5), +=4; ; .
, .
1) :
) 0,
) 1,
) ,
) xÎ (- ¥ ; 1)È (1; ¥ ).
2) :
) ,
) - 1,
) - 5,
) - 1; - 5.
3) :
s
) - 2; ; 5,
) ,
) xÎ (- ¥ ; 3)È (3; ¥ ),
) x Î R.
4) : ax = 1.
) a ¹ 0, xÎ R; a = 0, ,
) a = 0, ; a ¹ 0, x =1/a ,
) a = 0 , xÎ R; a ¹ 0, x =1/a .
) .
5) a ax2 - 4x + a + 3 = 0 ?) - 4 < a < 0,
) 0 < a < 1,
) aÎ (- ¥ ; 0)È (0; ¥ ),
) - 4 < a < 0; 0 < a < 1.
6) a (a - 2)x2
+ (4 - 2a)x + 3 = 0 ?) 2,
) Î (- ¥ ; 2)È (2; ¥ ),
) 5,
) - 4.
7) : | x2 - 1| + | a(x - 1)| = 0.
) a ¹ 0, x =1; a = 0, x = ± 1,
) ¹ 0, ; a = 0, x = 1.
) x = ± 1,
) .
8) :
y2 - x - 5 = 0.
) (4; 3), (4; - 3),
) (1; 2),
) ,
) xÎ R, y = ± 3.
9) :
) (1; - 1), (5; 5)
) ,
) (1;1),
) (- 2; 3), (3; - 2).
10) a 2x + a > 0 x + 1 - 3a > 0?
)2/7 ,
) ³2/7 ,
) a,
) £2/7 .
11) , :
) Î (-¥ ; -3,5),
) 3,
) 4,
) .
12) , :
)5,
) 3,
) 4,
) .
13) :
) 0, 1, 2,
) 4, 5,
) 7,
) .
14) :
)5,
) 3, -4, -5,
) 5,6,
) .
15) :
) (-¥ ; -3)È (0; 3,
) (3, 0)È (0; ¥ ),
) (5; 7),
) .
16) :
) (-¥ ; -3/25)È (0; ¥ ),
) (12, 0)È (7;9),
) (-¥ ;)È ( ; 5),
) .
.
) (-9; -5)È (0; 8),
) (8, -7)È (1;3),
) (-¥ ; -7)È (1; 3),
) .
18) :
.
) [-4; -2)È (0;5],
) (1, 0]È [1;7),
) (-4; -3)È [5; 7],
) .
19)
½ 1,5 3½ < 3.
) (-2,5; -2)È (0; 3,5],
) (0,5; 1,5),
) (-4,5; -3,5),
) .
20) :
) (-3; -1),
) (0; 1),
) (-7; -10),
) .
: 1 - ; 2 - ; 3 - ; 4 - ; 5 - ; 6 - ; 7 - ; 8 - ; 9 - ;10 ;
11 ; 12 ; 13 ; 14 ; 15 ; 16 ; 17 ; 18 ; 19 ; 20 .
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