Question

Please help! Fill in the missing number.

Answer 1

Answer:

21

Step-by-step explanation:

$\left[\begin{array}{cc}5&9\\-6&9\end{array}\right] +6\left[\begin{array}{cc}-5&2\\7&8\end{array}\right]$

Multiply the second matrix by 6.

$\left[\begin{array}{cc}5&9\\-6&9\end{array}\right] +\left[\begin{array}{cc}-30&12\\42&48\end{array}\right]$

Add the corresponding cells in each matrix.

$\left[\begin{array}{cc}5-30&9+12\\-6+42&9+48\end{array}\right]$

$\left[\begin{array}{cc}-25&21\\36&57\end{array}\right]$