6×(x-20)=3×(x-10) x=306×(x-20)=3×(x-10) x=30

问题描述:

6×(x-20)=3×(x-10) x=30
6×(x-20)=3×(x-10) x=30

6x-120=3x-30
6x-3x=120-30
3x=90
x=90÷3
x=30