Answer:
The values of A and B are -6 and -15 respectively.
Explanation:
For values for A and B which will create infinitely many solutions for this system of equations. the equation must follow this scheme ;
..[1]
..[2]

So we have ';
4x - Ay = 15..[1]
-4x + 6y = B..[2]



A = 6


B = -15
So, the values of A and B are 6 and -15 respectively.
4x - 6y = 15..[1]
-4x + 6y = -15..[2]