(x+20-10)乘3/10-(x-10)乘1/3=5 两边乘30
9(x+10)-10(x-10)=150
9x+90-10x+100=150
10x-9x=190-150
x=40
解:(x+20-10)×3/10-(x-10)×1/3=5
9(x+10)-10(x-10)=150
9x+90-10x+100=150
10x-9x=190-150
x=40