Solve the initial-value problem x ^{\prime}(t)=A x (t), x (0)= x _{0}, where
A=\left[\begin{array}{rr}1 & -1 \\1 & 3\end{array}\right] \quad \text { and } \quad x _{0}=\left[\begin{array}{r}5 \\-7\end{array}\right].
Solve the initial-value problem x ^{\prime}(t)=A x (t), x (0)= x _{0}, where
A=\left[\begin{array}{rr}1 & -1 \\1 & 3\end{array}\right] \quad \text { and } \quad x _{0}=\left[\begin{array}{r}5 \\-7\end{array}\right].