assumig 2nd euqation is y =-3x+11
using subtraction
minus y both sides and minus 11
-3x-y=-11
add to other equation to eliminate y's
-3x-1y=-11
3x+2y=7 +
0x+1y=-4
y=-4
sub back
y=-3x+11
-4=-3x+11
minus 11 both sides
-15=3x
divide both sides by 3
-5=x
(x,y)
(-5,-4)
