The graph below shows a function $y = af(x)\text{,}$ where $a$ is a constant number. Use the slider to change the value of the constant $a\text{,}$ and observe changes to the graph. Notice that $a$ is being multiplied by the output of the function $f\text{.}$

1. Change $a$ to a number greater than $1\text{.}$ What happened to the graph?
   Answer: The graph of $f$ was vertically ? stretched away from compressed toward the $x$– axis.
2. Change $a$ to a number between $0$ and $1\text{.}$ What happened to the graph?
   Answer: The graph of $f$ was vertically ? stretched away from compressed toward $x$– axis.

Next, the graph of a different function $y = af(x)$ is shown. This time, you can change $a$ to positive or negative values.

1. Change $a$ to the value $-2\text{.}$ What happened to the graph?
   Answer: The graph of $f$ was vertically ? stretched away from compressed toward by a factor of $2\text{,}$ and it was reflected over the ? x-axis y-axis line y = x .