Question 633334
Actually the answer is -2, 5, -2 not  -2, 5, 2
I don't know where you went wrong but after you found y=5
You could have gotten x=-2
1 1 0 3 
0 1 0 5 
1 0 0 -2

now we have 
1 0 0-2
0 1 0 5 
3 2 -4 12 
3 0 0 -6
0 2 -4 18
0 2 0 10 
0 0 -4 8
which leaves
0 0 1 -2