6％x+19x=22.5
0.06x+19x=22.5
19.06x=22.5
x=22.5/19.06=1.18
70％x-18％x=3.12
0.7x-0.18x=3.12
0.52x=3.12
x=6
28％x+37％x=22.75
0.28x+0.37x=22.75
0.65x=22.75
x=22.75/0.65=35
78％x=39
0.78x=39
x=39/0.78=50