# Math Help - Find a and b given f(x) and a horizontal tangent

1. ## Find a and b given f(x) and a horizontal tangent

$f(x)=\frac{ax+b}{(x-1)(x-4)}$

Horizontal tangent is at $(2,-1)$

How would I find $a$ and $b$?

2. Originally Posted by youngb11
$f(x)=\frac{ax+b}{(x-1)(x-4)}$
Horizontal tangent is at $(2,-1)$
How would I find $a$ and $b$?
You want $f(2)=-1~\&~f'(2)=0$.

3. Thanks! I'll see if I can take it on from there.