TeX source:

\begin{array}{ll} 6 p=12-2 n & \text { Subtract } 2 n \text { from both sides. } \\ p=\dfrac{12-2 n}{6} & \text { Divide both sides by } 6 \text { and simplify. } \\ p=\dfrac{12}{6}-\dfrac{2 n}{6} & \\ p=2-\dfrac{1}{3} n & \end{array}