Answer:
The first equation should be multiplied by - 7 and the second equation by 3
Explanation:
Indeed, let s multiply the first equation by -7
-7*9x-7*3y=7*18
and the second one by 3
3*8x+3*7y=3*10
when we add both the terms in y will be -7*3y+3*7y= 0
and then we can solve on x
hope this helps