1/2x-28=50
1/2x=50+28=78
x=156
x-2/7x=15/28
5x/7=15/28
x=3/4
3x-1.2=3.6
3x=3.6+1.2=4.8
x=1.6
x-20%x=7.2
80%x=7.2
x=9
0.9x+1.3x=5.28
2.2x=5.28
x=2.4
1/2x-28=50
1/2x=50+28=78
x=156
x-2/7x=15/28
5x/7=15/28
x=3/4
3x-1.2=3.6
3x=3.6+1.2=4.8
x=1.6
x-20%x=7.2
80%x=7.2
x=9
0.9x+1.3x=5.28
2.2x=5.28
x=2.4