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.

1) - (2x - 5) - (-Зх - 7) = - 3

-2 х+5+3 х+7=-3

-2 х+3 х=-3-5-7

х=-15

2) - (Зх + 2) - (7 - 5x) = - 6

-3 х-2-7+5 х=-6

-3 х+5 х=2+7-6

2 х=3

х=3:2

х=1.5

3) - 4 (x - 2) - 2 (1 - 4x) = 18

-4 х+8-2+4 х=18

-4 х+4 х=18-8+2

0 х=12

х=любое число

4) - 5 (x - 3) - (-7x - 1) = 2

-5 х+15+7 х+1=2

-5 х+7 х=2-1-15

2 х=-14

х=-14:2

х=-7