0.2x-4=0.15x
0.2x-0.15x=4
0.05x=4
x=4÷0.05
x=80验算之后不对呀0.2x80=1616-4=120.15x80=1212-12=00.2×80-4=120.15×80=1212=12怎么不对啊嘻嘻，逗你玩