25%x+3=3分之2*6 18-5%x=12.8 2x30%x=18.4

25%x+3=3分之2*6
0.25x+3=4
0.25x=4-3
0.25x=1
x=1÷0.25
x=4
18-5%x=12.8
18-0.05x=12.8
0.05x=18-12.8
0.05x=5.2
x=5.2÷0.05
x=104
2x30%x=18.4
2×0.3x=18.4
0.6x=18.4
x=18.4÷0.6
x=92/3
x=3分之92