Exercise 1.1.26

What combination $c\left[\begin{array}{c}1\hfill \\ 2\hfill \end{array}\right]+d\left[\begin{array}{c}3\hfill \\ 1\hfill \end{array}\right]$ produces $\left[\begin{array}{c}\hfill 14\\ \hfill 8\end{array}\right]?$ Express this question as two equations for the coefficients $c$ and $d$ in the linear combination.