These are two linear equations so they can have zero, one, or infinitely many solutions...
Subtracting one from the other eliminates x...
9x+y-9x+y=3-7
2y=-4
y=-2, making 9x+y=3 become:
9x-2=3
9x=5
x=5/9
So the single solution to this system of equations is the point (5/9, -2)