I'm going back over my calculus book now that the year is over, doing all the questions to make sure that I know the subject. I worked this limit problem and got it wrong but I don't know how to solve it correctly (without L'Hospital's).

$\displaystyle \lim_{x \to 7} \frac{\sqrt{x+2}-3}{x-7}$

I said DNE, but the answer is 1/6. Anyone know how to solve? thx.