x+(x+20)+(x-10)+70+x=540 .

问题描述:

x+(x+20)+(x-10)+70+x=540 .

答:
x+(x+20)+(x-10)+70+x=540
4x+20-10+70=540
4x+80=540
4x=460
x=115

70+(x+20)+(x-10)+x+x=540
4x+80=540
4x=540-80
4x=460
4x=460÷4
x=115