Plug in (-1, 3) into both equations
Ax - 2y = 4
A(-1) - 2(3) = 4
-A - 6 = 4 Add 6 on both sides
-A = 10 Divide -1 on both sides
A = -10
5x + By = -1
5(-1) + B(3) = -1
-5 + 3B = -1 Add 5 on both sides
3B = 4 Divide 3 on both side
B = [tex]\frac{4}{3}[/tex]
