Answer:
[1]XXXX9x−9y=27
[2]XXXX7y−3x=−11
Resequence the terms of [2] so the variables occur in the same order as in [1]
[3]XXXX−3x+7y=−11
Multiply [3] by 3
[4]XXXX−9x+21y=−33
Add [1] and [4]
[5]XXXX12y=−6
Divide [5] by12
[6]XXXXy=−12
Substitute y=−12 into [1]
[7]XXXX9x−9(−12)=27
Simplifying
[8]XXXX9x=452
[9]XXXXx=52
