(1)30%x+85=70%x+25,
30%x+85-30%x=70%x+25-30%x,
85-25=0.4x+25-25,
60÷0.4=0.4x÷0.4,
x=150;
(2)x÷(1-24%)=1.15
x÷(1-24%)×(1-24%)=1.15×(1-24%),
x=1.15×0.74,
x=0.851;
(3)
=5x+3 8+2x
,2 3
(5x+3)×3=(8+2x)×2,
15x+9=16+4x,
15x+9-4x=16+4x-4x,
11x+9-9=16-9,
11x÷11=7÷11,
x=
.7 11