GIven data:
The given matrices are shown.
The expression for -4A+6B is,
[tex]-4\begin{bmatrix}{-2} & {6} & {1} \\ {1} & {9} & {-6} \\ {-9} & {9} & {-9}\end{bmatrix}+6\begin{bmatrix}{-5} & {9} & {6} \\ {-2} & {-7} & {4} \\ {1} & {10} & {-1}\end{bmatrix}=\begin{bmatrix}{-22} & {30} & {32} \\ {-16} & {-78} & {48} \\ {42} & {24} & {30}\end{bmatrix}[/tex]Thus, the option (a) is correct.