4x-1.3*6=2.6
4x-7.8=2.6
4x=2.6+7.8
x=10.4/4
x=2.6
0.3*7+4x=12.5
2.1+4x=12.5
4x=12.5-2.1
x=10.4/4
x=2.6
120-9x=1.2*6.25
120-9x=7.5
9x=120-7.5
x=112.5/9
x=12.5