5+5x/6=80
5x/6=75
5x=450
x=90
x-x/5=24
4x/5=24
4x=120
x=30
x/2+x/3=55
5x/6=55
5x=330
x=66
2x/5-x/4=36
3x/20=36
3x=720
x=240