I'm not sure if I have this correct I have to solve each literal equation for the indicated variable. A=1/2h(B+b)variable is (b). I have the answer as:

2A=h(B1+b2)
2A/h=B1+b2
(2A/h)-b2=B1
Is this correct?

weren't you supposed to solve for "b"?

that would be

b = (2A - Bh)/h or 2A/h - B

(looks similar in pattern to your last line)