Question

已知x、y满足方程组{7x+6(x-y)=130,则x--y的值是（ ）.{7y-2(x-y)=10

Answer 1

7x+6(x-y)=130.1

7y-2(x-y)=10 .2

1式-2式得

7(x-y)+4(x-y)=120

11(x-y)=120

x-y=120/11