# How do you find the domain of #f(x) = (x+18 )/( x^2-169)#?

##### 2 Answers

#### Explanation:

The denominator of f(x) cannot be zero as this would make f(x) undefined. Equating the denominator to zero and solving gives the values that x cannot be.

#"solve "x^2-169=0rArr(x-13)(x+13)=0#

#rArrx=+-13larrcolor(red)" excluded values"#

#rArr"domain is "x inRR,x!=+-13#

The domain is

#### Explanation:

The denominator must

Therefore,

Let

Construct a sign chart

Therefore,

This is the domain of

graph{(x+18)/(x^2-169) [-20.27, 20.28, -10.14, 10.14]}