2(x+15)=x-10 4(x+7)=2(x-1) -7( x+1)=21 6(x-0.5)-x=12 ..

问题描述:

2(x+15)=x-10 4(x+7)=2(x-1) -7( x+1)=21 6(x-0.5)-x=12 ..

2(x+15)=x-10
2x+30=x-10
2x-x=-30-10
x=-40
4(x+7)=2(x-1)
4x+28=2x-2
4x-2x=-28-2
2x=-30
x=-15