Question 2

Explanation

Given $AB = \begin{pmatrix} 1 & 3 \\ 17 & 11 \end{pmatrix}$. Calculate the product $AB$

Equate with $\begin{pmatrix} 1 & 3 \\ 17 & 11 \end{pmatrix}$

Eliminate $a$ by multiplying equation $\text{(1)}$ by $2$

Subtract equation $\text{(1a)}$ from equation $\text{(2)}$

Substitute $b = 3$ into equation $\text{(1)}$

With $a = 2$ and $b = 3$, matrix $B$ is

Calculate $D = 3A + B$