If the line tangent to the graph of the function $f$ at the point $(2,7)$ passes through the point $(-3,-3)$ then $f'(2)$ is...?
A. 5 B.1 C. 2 D.7 E. Undefined
I don't understand how to do this. I know that I can find the slope of the line tangent to the point $(2,7)$ but after I find that equation of the line how do I find $f'(2)$?