x-1/5x-(1/5x+15)=1/2x

问题描述:

x-1/5x-(1/5x+15)=1/2x

x-1/5x-(1/5x+15)=1/2x
x-1/5x-1/5x-15=1/2x
3/5x-1/2x=15
1/10x=15
x=150