16+8x = 40
8x=40-16
8x=24
x=3
4x-3×9 = 29
4x-27=29
4x=29+27
4x=56
x=14
5X=2.2
x=2.2÷5
x=0.44
3x+6 = 18
3x=18-6
3x=12
x=4
2x-7.5 = 8.5
2x=8.5+7.5
2x=16
x=8