Originally Posted by

**euclid2** Determine an expression, in simplified form, for the slope of the secant PQ

a) $\displaystyle P(1,3), Q(1+h,f(1+h))$, where $\displaystyle f(x)=3x^2$

Now, i know which formula to use, which is

$\displaystyle Limh->0 \frac{(x+h)-f(x)}{h}$

i have the solution to this problem, but don't understand where the numbers are coming from so it's useless to me. i don't understand how to plug the numbers into this formula

for the first step it is:

$\displaystyle Limh->0 \frac{3(1+h)^2-3}{h}

$

then simply simplifying to get

3h+6

can someone please explain this to me?