2X-4=16
2X=4+16
2X=20
X=20/2
X=10
1.5X-3=60
1.5X=3+60
1.5X=63
X=63/1.5
X=42
3.4X-4*3=52
3.4X-12=52
3.4X=52+12
3.4X=64
X=64÷3.4
X=320/17
X除以2分之1=4分之3
X=3/4*1/2
X=3/8