y=mx+c

I think you want the equation of a line that passes through those points.

 

\(slope=m=\frac{y_1-y_2}{x_1-x_2} \\~\\ y_1=3,y_2=9,x_1=2,x_2=3 \\~\\ m=\frac{3-9}{2-3}=\frac{-6}{-1}=6\)

 

 

Now to find c, just plug in one of the points using the m that we found and solve for c.

 

y = mx + c

y = 6x + c

3 = 6(2) + c

3 = 12 + c

3 - 12 = c

-9 = c

 

Now put it together:

y = 6x - 9