5x-1.6=9/10
5x=0.9+1.6
5x=2.5
x=0.5
3/4x+1/2X=2又1/4
5x/4=9/4
5x=9
x=9/5
3又1/3x－1.75乘10=54.2
10x/3=54.2+17.5
10x=71.7×3
x=21.51