## Precalculus (6th Edition) Blitzer

$f(x)=-\dfrac{x}{4}+\dfrac{5}{4}$
We need to find the line equation by using two points such as: $(1,1); (2,-3)$ $\dfrac{y-1}{-3-1}=\dfrac{x-1}{2-1}$ This gives: $y-1= -4x+4$ or, $x=\dfrac{-y+5}{4}=-\dfrac{y}{4}+\dfrac{5}{4}$ Thus, we have the linear equation for the function $f(x)$ is $f(x)=-\dfrac{x}{4}+\dfrac{5}{4}$