​ graph variables

This is a line so the equation is like \((y-y1)=\frac{(y1-y2)}{(x1-x2)}(x-x1) \),\((x1,y1)=(0,0) , (x2,y2)=(20,15) \)

\((y-0)=\frac{(0-15)}{(0-20)}(x-0) <=> y=\frac{15}{20}x\)

The equation is \(y=\frac{15}{20}x \)

 

Hope this helps!