Answer
$$a = \frac{2A}{h} - b$$
Work Step by Step
To solve for $a$, we need to isolate $a$:
We first divide each side by $\frac{1}{2}$, which means we need to multiply by the inverse of $\frac{1}{2}$, which is $2$:
$$2A = h(a + b)$$
We then divide each side by $h$:
$$\frac{2A}{h} = a + b$$
We now subtract $b$ from each side:
$$a = \frac{2A}{h} - b$$
