Exercise 4 Page 175

An equation in point-slope form follows a specific format. In this form, $m$ is the slope and the point $(x_1,y_1)$ lies on the line. We are given the point $(3,5)$ and the slope $\text{-}1,$ so we have everything we need to create a point-slope form equation. Please note that this is only one of infinitely many possible equations for this line because any point lying on the line could be used to create an equivalent equation. However, since we were given a point, this equation was the easiest to form.