Answer:
[tex]y=\frac{5}{8}x+20[/tex]
Step-by-step explanation:
I'll start by finding the slope of this line using the slope formula:
[tex]\frac{70-20}{80-0}\\\frac{50}{80}\\\frac{5}{8}[/tex]
Just by looking at the graph I know that the y-intercept is 20, so now I can write the equation in slope-intercept form (y=mx+b):
[tex]y=\frac{5}{8}x+20[/tex]
