Exercise 23 Page 175

Notice that the given two points, $f(2)=\text{-}2$ and $f(1)=1,$ are in function notation. To start, let's write these points as coordinate pairs. Remember that the input $x$ is the $x\text{-}$coordinate and the output $f(x)$ is the $y\text{-}$coordinate. Now, we are able to write an equation for function $f$ in slope-intercept form. However, we cannot determine the $y\text{-}$intercept of the equation from the given points. Therefore, we will follow three steps.

1. We will first find the slope of the equation by using the Slope Formula.
2. Next, we will write the equation in point-slope form.
3. Finally, we will rearrange the equation to write it in slope-intercept form.