the first one we see that the intersection is 3 units to the right and 6 uniits down or x=3 and y=-6 (down=-) so the point is (3,-6)
the solutions (1,2)
we subsitute and find that the answer is the first equation
we add them together and get
we negative the first and add
-2x+2x+y+y=5+5
2y=10
y=10
sutaitute
2x-y=-5
2x-10=-5
we can see that there is 1 solution