Chapter 8 - Systems of Linear Equations and Problem Solving - 8.6 Elimination Using Matrices - 8.6 Exercise Set - Page 551: 17

$$p=4,\:r=-\frac{1}{2},\:q=\frac{1}{2}$$

Solving the system of equations using Matrices, we find: $$ \begin{bmatrix}3&2&0&¦&11\\ 0&-7&1&¦&4\\ 1&0&-6&¦&1\end{bmatrix}\\ \begin{bmatrix}1&0&0&¦&4\\ 0&1&0&¦&-\frac{1}{2}\\ 0&0&1&¦&\frac{1}{2}\end{bmatrix}\\ p=4,\:r=-\frac{1}{2},\:q=\frac{1}{2}$$