# Math Help - the derivative function

1. ## the derivative function

given that f(3)=-1 and f '(3)=5, find an equation for the tangent line to the graph of y=f(x) at x=3

no idea where to start

2. There is a formula stating that the equation of the tangeant to a curve at point A (a, f(a)) is:

y-f(a)=(x-a)f'(a)

civodul

3. i know the answer is y=5x-16 but not seeing how you get to that from that equation

4. Just plug in the values for the formula

$y - (-1) = 5(x-3)$

and then simplify