9.31. Решите уравнение: 1) -(2x - 5) - (-Зх - 7) = -3; 2) -(Зх + 2) - (7 - 5x) = -6; 3)...

Question

9.31. Решите уравнение: 1) -(2x - 5) - (-Зх - 7) = -3;
2) -(Зх + 2) - (7 - 5x) = -6;
3) -4(x - 2) - 2(1 - 4x) = 18;
4) -5(x - 3) - (-7x - 1) = 2.

Answer 1

1) -(2x - 5) - (-Зх - 7) = -3
-2х+5+3х+7=-3
-2х+3х=-3-5-7
х=-15

2) -(Зх + 2) - (7 - 5x) = -6
-3х-2-7+5х=-6
-3х+5х=2+7-6
2х=3
х=3:2
х=1.5

3) -4(x - 2) - 2(1 - 4x) = 18
-4х+8-2+4х=18
-4х+4х=18-8+2
0х=12
х=любое число

4) -5(x - 3) - (-7x - 1) = 2
-5х+15+7х+1=2
-5х+7х=2-1-15
2х=-14
х=-14:2
х=-7