18-120%x=6
18-1.2x=6
1.2x=18-6
1.2x=12
x=12÷1.2
x=10
1.75x-1.2×45%=1.56
1.75x- 0.54=1.56
1.75x=1.56+0.54
1.75x=2.1
x=2.1÷1.75
x=1.2