## Introductory Algebra for College Students (7th Edition)

$$b = 2A - a$$
To solve this equation for $b$, we need to isolate $b$. We first divide both sides by $\frac{1}{2}$, which means we will multiply each side by the inverse, which is $2$: $$2A = a+b$$ We then subtract $a$ from each side: $$b = 2A - a$$