Question

$m\left[\begin{array}{cc}-3& 4\end{array}\right]+n\left[\begin{array}{cc}4& -3\end{array}\right]=\left[\begin{array}{cc}10& -11\end{array}\right]\Rightarrow 3m+7n=$

• A. 3
• B. 5
• C. 10
• D. 1

Answer 1

Answer: (D)

$m\left[\begin{array}{cc}-3& 4\end{array}\right]+n\left[\begin{array}{cc}4& -3\end{array}\right]=\left[\begin{array}{cc}10& -11\end{array}\right]$
$\Rightarrow -3m+4n=10,4m-3n=-11$
$\Rightarrow m=-2,n=1$
$\therefore 3m+7n=-6+7=1$