Answer:
Given, \[(4A-3B)=4A+(-\,3B)\] Now, \[4A=\left[ \begin{matrix} 4\cdot 3 & 4\cdot 5 \\ 4\cdot 7 & 4\cdot (-\,9) \\ \end{matrix} \right]=\left[ \begin{matrix} 12 & 20 \\ 28 & -\,36 \\ \end{matrix} \right]\] and \[-\,3B=(-\,3)\cdot B=\left[ \begin{matrix} (-\,3)\cdot 6 & (-\,3)\cdot (-\,4) \\ (-\,3)\cdot 2 & (-\,3)\cdot 3 \\ \end{matrix} \right]\] \[=\left[ \begin{matrix} -\,18 & 12 \\ -\,6 & -\,9 \\ \end{matrix} \right]\] \[\therefore \] \[4A-3B=4A+(-\,3B)\] \[=\left[ \begin{matrix} 12 & 20 \\ 28 & -\,36 \\ \end{matrix} \right]+\left[ \begin{matrix} -\,18 & 12 \\ -\,6 & -\,9 \\ \end{matrix} \right]\] \[=\left[ \begin{matrix} 12+(-\,18) & 20+12 \\ 28+(-\,6) & -\,36+(-\,9) \\ \end{matrix} \right]=\left[ \begin{matrix} -\,6 & 32 \\ 22 & -\,45 \\ \end{matrix} \right]\] Hence, \[(4A-3B)=\left[ \begin{matrix} -\,6 & 32 \\ 22 & -\,45 \\ \end{matrix} \right]\]
You need to login to perform this action.
You will be redirected in
3 sec