Пошаговое объяснение:
1) 5x/6 - x/6 = 1
4x/6 = 1
x = 6/4 = 1,5
2) 3y/8 - y/4 = -1
y/8 = -1
y = -8
3) 9x/60 - x/20 = 1
6x/60 = 1
x = 60/6 = 10
4) x/9 - x/6 = 1/2
-x/18 = 1/2
x = -9
