To find the equation of the line in its slope-intercept form, you can take two points through which the line passes, find the slope of the line, and then use the point-slope formula.
For example, you can take the points (0,5) and (6,3).
The formula to find the slope of the line is
[tex]\begin{gathered} m=\frac{y_{2}-y_{1}}{x_{2}-x_{1}} \\ \text{ Where m is the slope of the line and } \\ (x_1,y_1),(x_2,y_2)\text{ are two points through which the line passes} \end{gathered}[/tex]So, you have
[tex]\begin{gathered} (x_1,y_1)=(0,5) \\ (x_2,y_2)=(6,3) \\ m=\frac{3-5}{6-0} \\ m=\frac{-2}{6} \\ m=-\frac{1}{3} \end{gathered}[/tex]Now using the point-slope formula you have
[tex]\begin{gathered} y-y_1=m(x-x_1) \\ y-5=-\frac{1}{3}(x-0) \\ y-5=-\frac{1}{3}x \\ \text{ Add 5 from both sides of the equation} \\ y-5+5=-\frac{1}{3}x+5 \\ y=-\frac{1}{3}x+5 \end{gathered}[/tex]The equation of a line in its slope-intercept form is
[tex]\begin{gathered} y=mx+b \\ \text{ Where m is the slope of the line and} \\ b\text{ is the y-intercept} \end{gathered}[/tex]Therefore, the equation of the line shown in the graph, in its slope-intercept form is
[tex]y=-\frac{1}{3}x+5[/tex]