3.25×7,.8-7.8
=(3.25-1)×7.8
=17.55
(5x-4)÷5=4
5x-4=20
5x=24
x=4.8
5x-3x1.3=0
5x=3.9
x=0.78
(x+0.5)×3=45
x+0.5=15
x=14.5