# Math Help - Derivative help

1. ## Derivative help

It then says I need to find

I just can't find this in my book. Please help!

2. Originally Posted by Bilbo94

It then says I need to find

I just can't find this in my book. Please help!
Treat the fraction as the following: $(x+3)^{-1}$

It's derivative follows the power rule... $(-1)(x+3)^{-1-1}$

which simplifies to: $-(x+3)^{-2}$

Plug and chug for $f'(-7)$

3. ## Thanks

Thanks so much!