Question

Given \[2\begin{bmatrix}x&5\\7&y-3\end{bmatrix}+\begin{bmatrix}3&-4\\1&2\end{bmatrix}=\begin{bmatrix}7&6\\15&14\end{bmatrix}\], what is the value of \[y\]?

Options

• \[y=9\]

• \[y=18\]

• \[y=7\]

• \[y=6\]

Answer 1

Equating the corresponding bottom-right elements gives \[2y-4=14\]. Thus, \[2y=18\], so \[y=\frac{18}{2}=9\].