3/7(5х-8)=-12
3/4(2у+1)+5=5,5

Пошаговое объяснение:

3/7(5х-8) = -12

5x - 8 = -12 * 7/3

5x - 8 = -28

5x = -28+8

5x = -20

x = -20:5

x = -4

3/4(2у+1)+5=5,5

3/4(2y + 1) = 5,5 - 5

3/4(2y + 1) = 0,5

2y + 1 = 1/2 * 4/3

2y + 1 = 2/3

2y = 2/3 - 1

2y = -1/3

y = -1/3 * 1/2

y = -1/6