Precalculus Examples

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

Step 1

Set the denominator in $\frac{1}{x + 4}$ equal to $0$ to find where the expression is undefined.

$x + 4 = 0$

Step 2

Subtract $4$ from both sides of the equation.

$x = - 4$

Step 3

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

Interval Notation:

$(- \infty, - 4) \cup (- 4, \infty)$

Set-Builder Notation:

${x | x \neq - 4}$

Step 4