Answer :

2y= 7x+18
6x+ 3(7x+18)=0
6x+21x+54=0
27x=-54
x=-2

6(-2)+6y=0
6y=12
y=2

6(-2)+6(2)=0
-12+12=0 True

-7(-2)+2(2)=18
14+4=18 True