Chapter 4 - Exponential and Logarithmic Functions - Section 4.4 Logarithmic Functions - 4.4 Assess Your Understanding - Page 322: 93

$5$

$\because y = \ln{x} \text{ is equivalent to } x=e^y$ $\therefore 5 = \ln{e^x} \text{ is equivalent to } e^x=e^5$ Solve the equation above using the rule $a^m=a^n\implies m=n$ to obtain: \begin{align*} e^x&=e^5\\ x&=5 \end{align*}