Find the Domain f(x)=(x+9)/(x-3)

$f (x) = \frac{x + 9}{x - 3}$

Step 1

Set the denominator in $\frac{x + 9}{x - 3}$ equal to $0$ to find where the expression is undefined.

$x - 3 = 0$

Step 2

Add $3$ to both sides of the equation.

$x = 3$

Step 3

The domain is all values of $x$ that make the expression defined.

Interval Notation:

$(- \infty, 3) \cup (3, \infty)$

Set-Builder Notation:

${x | x \neq 3}$

Step 4