x-0.72x=33.6
0.28x=33.6
x=33.6/0.28
x=120
7x-6.2×0.3=0.94
7x-1.86=0.94
7x=1.86+0.94
7x=2.8
x=2.8/7
x=0.4
1.6（5+x）=9.6
5+x=9.6/1.6
5+x=6
x=6-5
x=1