This is actually from my calculus textbook, but its in the first chapter which is all pre-calculus review. Unfortunately, I never was taught about difference quotients. Do they come up in calculus alot? Anyway, here's the prob:

If $\displaystyle f(x)=x^2-2x+3$, evaluate the difference quotient

$\displaystyle \frac{f(a+h)-f(a)}{h}$