20x+10x+50(20-2x)=440 怎么解
问题描述:
20x+10x+50(20-2x)=440 怎么解
答
20x+10x+50(20-2x)=440
20x+10x+1000-100x=440
100x-20x-10x=1000-440
70x=560
x=560/70
x=8