use the process of elimination, once you solve, it will give you one variable that will work for both equations, once you plug that in, it will give you the other variable.
7x + 3y = 13
2x -3y = -4
add the "y"; 3y + (-3y) = 0
9x = 9
x = 1
plug in the "x" value into either question to solve for "y"
7(1) + 3y = 13
7 + 3y = 13
3y = 6
y = 2