Determine whether y varies directly with . If so, find the constant of variation and write the equation.

Answer:
Yes,[tex]k=-\frac{1}{3}[/tex] and [tex]y=-\frac{1}{3}x[/tex]
Step-by-step explanation:
Using (-6,2) and (-9,3)
We have [tex]k=\frac{2-3}{-6--9}=-\frac{1}{3}[/tex]
This implies that;
[tex]y=-\frac{1}{3}x[/tex]
Checking for the third point,
When x=-15,
[tex]y=-\frac{1}{3}(-15)=5[/tex]
Hence y varies directly as x.