\(\text{A vector matrix is a matrix with one column, and expressed as a }{\rm 2}\times {\rm 1} \text{matrix is }\left[\begin{array}{c} {a_{11} } \\ {a_{21} } \end{array}\right] . \)

\(\text{To reflect a vector across the {y}-axis using matrices, we multiply the vector by the matrix }\left[\begin{array}{cc} {-1} & {0} \\ {0} & {1} \end{array}\right] \)

\(\text{What is the resulting vector if we rotate the vector matrix }\left[\begin{array}{c} {-5} \\ {8} \end{array}\right] \text{across the {y}-axis}?\)