x-0.6x+6=8.8,
0.4x=8.8-6
x=2.8÷0.4
x=7
x*(1-25%)=75,
x*75%=75
x=75÷75%
x=100
3x+7分之2=7分之5,
3x=5/7-2/7
x=3/7÷3
x=1/7
2分之1x+8分之1x=25
5/8x=25
x=25÷5/8
x=40