4.5x-6-4x=20
(x-0.6)×12%-0.04x
(4.5-4)x=20+6
0.5x=26
x=52
=0.12x-0.072-0.04x
=(0.12-0.04)x-0.072
=0.08x-0.072
1. x=52
2. 0.08x-0.072