Пошаговое объяснение:
80:(7x+5)=2
7x+5 = 80:2
7x+5 = 40
7x = 40 - 5
7x = 35
x = 35:7
x = 5
20-4(2x-3)=20
20 - 8x + 12 = 20
32 - 8x = 20
8x = 32 - 20
8x = 12
x = 12 : 8
x = 1,5
