Question 1001701

Hi there,
6x - y = -9.......(1)
4 + 7x = -y.......(2)
Sort Equation (2) out 
into y = mx + c form
6x - y = -9.......(1)
7x + y = -4.......(2)
Add (1) and (2)
13x = -13
x = -1
Substitute x = -1 into (1)
6x - y = -9
6(-1) - y = -9
-6 - y = -9
-y = -9 + 6
-y = -3
y = 3
{-1,3}
Hope this helps :-)