Intermediate Algebra, Chapter 2, 2.2, Section 2.2, Problem 6

Solve $P = a + b + c$ for $b$.

a.) For $b$


$\begin{equation} \begin{aligned} P =& a + b + c && \text{Given equation} \\ P - a - c =& a + b + c - a - c && \text{Subtract each side by $(a+c)$} \\ b =& P - a - c && \text{Solve for $b$} \end{aligned} \end{equation}$


b.) For $c$


$\begin{equation} \begin{aligned} P =& a + b + c && \text{Given equation} \\ P - a - b =& a + b + c - a - b && \text{Subtract each side by $(a+b)$} \\ c =& P - a - b && \text{Solve for $c$} \end{aligned} \end{equation}$