(A+6B)/2 = -3 and (B+2A)/2 = 5
So, A+6B = -6
2A+ B = 10
Multiply the first equation by - 2: -2A - 12B = 12
2A + B = 10
Adding the equations, we have -11B = 22
B = -2
Since A+6B = -6 and B = -2, we get A = 6