We want to put b alone on one side of the equation.
If we multiply by 1/2, we get 1/4bh = A/2. Not only did we not remove a variable from the left side, we made it even more complicated.
So the answer is A.
8x - 2y = 48, y =4
8x - 2(4) = 48
8x - 8 = 48
8x = 48+8
8x = 56
x = 56/8 = 7
x = 7
The correct answer is the second answer choice.