-7. х +2 . (3+х )= 3.х +5.(х-2)

-7 · х + 2 · (3 + х) = 3 · х + 5 · (х - 2)

-7х + 6 + 2х = 3х + 5х - 10

-5х + 6 = 8х - 10

-5х - 8х = -10 - 6

-13х = -16

х = -16 : (-13)

х = 16/13

х = 1 целая 3/13

Проверка:

-7 · 16/13 + 2 · (3 + 16/13) = 3 · 16/13 + 5 · (16/13 - 2)

-112/13 + 2 · 55/13 = 48/13 + 5 · (-10/13)

-112/13 + 110/13 = 48/13 - 50/13

-2/13 = -2/13