>>536258628
this is the one in the bottom left corner.
since it's already given that X = 1 and Y = 2 from how it starts and both rows and columns contain 2* A that makes both sums =18+2A so A doesn't matter and B has to be 0.
and A should be 1,2 or 3. anything higher wouldn't work.
But i don't know where to go from there.