## Precalculus: Concepts Through Functions, A Unit Circle Approach to Trigonometry (3rd Edition)

$b=4$
Recall the logarithmic property: When $a^x=y$, then $\log_a y =x$ and vice-versa. Applying this rule, we obtain: $\log_b \ 16=2 \\ b^2=16$ Simplify the equation to obtain: $b^{2}=16 \\ b^2 =4^2$ Apply the rule: $a^m=a^n \longrightarrow m=n$ if $a\ne1,a\ne-1$ So, $b=4$