point slope formular is as follows
[tex]\begin{gathered} y-y_1=m(x-x_1) \\ \text{where} \\ m=\text{slope} \end{gathered}[/tex]The point slope form using the graph can be represented below. let us find the slope first
[tex]\begin{gathered} m=\frac{y_2-y_1}{x_2-x_1} \\ m=\frac{400-175}{8-3} \\ m=\frac{225}{5}=45 \end{gathered}[/tex]using one point on the graph(3, 175) to represent the point slope equation is represented below
[tex]\begin{gathered} y-175=45(x-3) \\ y-175=45x-135 \\ y=45x-135+175 \\ y=45x+40 \end{gathered}[/tex]