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

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

\(\text{What is the value of cell a_{21} in the resulting vector if we rotate the vector matrix} \left[\begin{array}{c} {-14} \\ {-45} \end{array}\right] \text{across the {y}-axis?}\)

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