In Exercises $1-4,$ find the vector $\mathbf{x}$ determined by the given coordinate vector $[\mathbf{x}]_{\mathcal{B}}$ and the given basis $\mathcal{B} .$
$$
\mathcal{B}=\left\{\left[\begin{array}{l}{4} \\ {5}\end{array}\right],\left[\begin{array}{l}{6} \\ {7}\end{array}\right]\right\},[\mathbf{x}]_{\mathcal{B}}=\left[\begin{array}{r}{8} \\ {-5}\end{array}\right]
$$