Question

Please help me. I don’t understand matrices

Answer 1

A.
`\orange {\begin{bmatrix} 4 & 11 \\ 3 & 0 \end{bmatrix}}`

Explanation:

`A= \begin{bmatrix} 5 & - 8 \\ 3 & 0\end{bmatrix} \: and \: B= \begin{bmatrix} 2 & - 9 \\ 1 & 0\end{bmatrix}`

`\therefore 2A= 2\begin{bmatrix} 5 & - 8 \\ 3 & 0\end{bmatrix} \: and \: \: 3B= 3\begin{bmatrix} 2 & - 9 \\ 1 & 0\end{bmatrix}`

`\therefore 2A= \begin{bmatrix} 10 & - 16 \\ 6 & 0 \end{bmatrix} \: and \: \: 3B= \begin{bmatrix} 6 & - 27 \\ 3 & 0\end{bmatrix}`

`\therefore 2A-3B= \begin{bmatrix} 10 & - 16 \\ 6 & 0 \end{bmatrix} - \begin{bmatrix} 6 & - 27 \\ 3 & 0 \end{bmatrix}`

`\therefore 2A-3B= \begin{bmatrix} 10-6 & - 16-(-27) \\ 6-3 & 0-0 \end{bmatrix}`

`\therefore 2A-3B= \begin{bmatrix} 4 & - 16+27 \\ 3 & 0 \end{bmatrix}`

`\huge \red {\therefore 2A-3B= \begin{bmatrix} 4 & 11 \\ 3 & 0 \end{bmatrix}}`