Precalculus Examples

$\log_{2} (x + 15) = 4$

Step 1

Rewrite $\log_{2} (x + 15) = 4$ in exponential form using the definition of a logarithm. If $x$ and $b$ are positive real numbers and $b \neq 1$ , then $\log_{b} (x) = y$ is equivalent to $b^{y} = x$ .

$2^{4} = x + 15$

Step 2

Solve for $x$ .

Tap for more steps...

Step 2.1

Rewrite the equation as $x + 15 = 2^{4}$ .

$x + 15 = 2^{4}$

Step 2.2

Raise $2$ to the power of $4$ .

$x + 15 = 16$

Step 2.3

Move all terms not containing $x$ to the right side of the equation.

Tap for more steps...

Step 2.3.1

Subtract $15$ from both sides of the equation.

$x = 16 - 15$

Step 2.3.2

Subtract $15$ from $16$ .

$x = 1$