I have the function:

$\displaystyle f(x)=5x+6$

I need to "find the derivative by the limit process".

Using:

$\displaystyle (f(x+deltax)-f(x))/deltax$

My work:

$\displaystyle (5(x+deltax)+6-(5x+6))/deltax$

$\displaystyle (5x+5deltax+6-(5x+6))/deltax$

The two 5x's go away, the 5Δx and Δx go away, so I'm left with 12, which isn't the answer.

I'm lost.