Answer:
A
Step-by-step explanation:
This question is just asking you to solve for a! That means they want you to move a to one side, and the rest of the equation to the other.
First, you can divide both sides by h, which will give you A/h = (a+b)/2
Second, you will multiply both sides by 2 -> 2A/h = a+b
Lastly, to get a isolated you need to subtract b, so 2A/h - b = a
