:
{3*x + 2*y = 10;
{5*x + 3*y = 12;
, , . , .
{3*x+2*y=10 |*3
{5*x + 3*y = 12 |*2
:
{9*x+6*y = 30;
{10*x+6*y=24;
. .
10*x+6*y (9*x+6*y) = 24-30; x=-6;
.
{3*(-6) + 2*y =10;
{2*y=28; y =14;
x=6 y=14. . .
{3*x + 2*y = 10;
{5*x + 3*y = 12;
{3*(-6) + 2*(14) = 10;
{5*(-6) + 3*(14) = 12;
{10 = 10;
{12=12;
, , , .
: (6, 14)
7. :
- ;
- .
, .
y = x n ( )
, y = x 2 ax 4 + bx 2 + c = 0, a ≠ 0 .
1
(x 2 + x + 1)(x 2 + x + 2) = 12.
t = 4 t = 3. .
1) , .
2) x = 1 x = 2.
. x = 1 x = 2.
8. , . , (), , . , . , . .
.
|x + 1| + |2x 4| |x + 3| = 2x 6.
1) , . , .
x + 1 = 0 2x 4 = 0 x + 3 = 0
x = - 1 2x = 4 x = - 3
x = 2
2) . .
3) , . . , +, , . :
|
|
4) , , . , :
I (-∞; -3). . :
- (x + 1) (2x 4) (- (x + 3)) = 2x 6. , :
- x 1 2x + 4 + x + 3 = 2x 6
- 4x = - 12
x = 3.
, .
II [-3; -1). , , +. :
- (x + 1) (2x 4) (x + 3) = 2x 6. , :
- x 1 2x + 4 x 3 = 2x 6. :
- 5x = - 6
x = 6/5. , .
III [-1; 2). , . :
(x + 1) (2x 4) (x + 3) = 2x 6. , , x , x . :
x + 1 2x + 4 x 3 = 2x 6
- 4x = -8
x = 2.
2 .
IV [2; +∞). +. :
(x + 1) + (2x 4) (x + 3) = 2x 6.
x + 1 + 2x 4 x 3 = 2x 6
0 = 0.
. , . , , , x ≥ 2.
: x ≥ 2.
9. .
x, y, z, O. . xy, xz yz.
x, y z .
xy, xz yz .
O - x, y z .
x A , OAx: , Ax x, , .
A : A(x;y;z)
, - .
, - . , - , - .
, - Ox, Oy, Oz.
10. (1; 1) (2; 2)