Slope of the tangent line at (2,5)

Find the slope of the tangent line at (2,5)
f(x) = x²+1

Please use this formula:
http://i45.tinypic.com/33nvod2.png

Thank you for the help in advance!

Well you are given the formula, why not use it?

I have tried using the formula and keep getting the wrong answer; otherwise I obviously wouldn't have posted a question on here..

Attachment 26823

Thank you, I figured out what I did wrong. I made a simple error when multiplying numbers together.