#### Answer

Av = $\begin{bmatrix}
4\\
6\\
\end{bmatrix}$
The transformation is a vertical stretch by a factor of 3.

#### Work Step by Step

First rewrite the vector as a matrix:
v = $\begin{bmatrix}
4\\
2\\
\end{bmatrix}$
Then multiply the two matrices to find Av:
Av = $\begin{bmatrix}
1(4) + 0(2)\\
0(4) + 3(2)\\
\end{bmatrix}$ = $\begin{bmatrix}
4\\
6\\
\end{bmatrix}$
The transformation is a vertical stretch by a factor of 3.