7×2.5-2X=7.2
17.5-2X=7.2
2X=17.5-7.2
2X=10.3
X=5.15
5.5m-0.5m=0
5m=0
m=0
5X-1.2=6.8
5X=6.8+1.2
5X=8
X=1.6