7x - 9y =29 ---------(1)
7x +2y = -15 ----------------(2)
On subtracting (2) from (1) we get:
-11y = 44
or y = -44/11 = -4
On putting the value of y in (1) we get:
7x - 9(-4) =29
or 7x +36 =29
or 7x = 29-36 = -7
or x = -7/7
or x = -1
so, x=-1 and y =-4