4x=6.8-1.8
4x=5
x=5/4
3/5x=4-3/10
3/5x=37/10
x=37/10 /(3/5)
x=6又6分之1
(9.5-4)x=2.75
5.5x=2.75
x=2.75/5.5
x=0.5