# Math Help - Derivative

1. ## Derivative

To find the derivative of $f(x)=x^2-3x+21$ at $x=4$, would you just find the derivative of $f(x)$, which is $2x-3$, and plug in 4 for $x$, to get 5?
Thanks!

2. Originally Posted by live_laugh_luv27
To find the derivative of $f(x)=x^2-3x+21$ at $x=4$, would you just find the derivative of $f(x)$, which is $2x-3$, and plug in 4 for $x$, to get 5?
Thanks!
yes ... $f'(4) = 5$