Переносим -18 направо
х= 1600:4+18
х=418
2/3(1 1/2х+3/5)-4/5(5/12х-1/2)=1 3/6
2/3 (3/2х +3/5) - 4/5 (5/12х - 1/2) = 9/6
х + 2/5 - 1/3х + 2/5 = 9/6
х -1/3х = 9/6 -2/5 -2/5
3-1/3 х = 45- 12-12 /30
2/3х = 21/30
х = 21/30 : 2/3
х = 21/30*3/2
х = 21/20
х = 1 1/20