- #1

- 392

- 13

## Homework Statement

If a and b satisfy ##\lim_{x->0}\frac{\sqrt{ax+b}-5}{x} = \frac{1}{2}##, then a+b equals...

A. -15

B. -5

C. 5

D. 15

E. 30

## Homework Equations

L'hospital

## The Attempt at a Solution

By using L'hospital, I get b=a^2

Then, I got stuck.. Substituting b=a^2 into the limit equation, but I still can't cancel out the x which is the cause of zero denominator..

Please help