Answer
$\approx 2.8074$
Work Step by Step
RECALL:
The change-of-base formula for logarithms:
$$\log_a{b} = \dfrac{\log_c{b}}{\log_c{a}}$$
Most calculators have the common logarithm $\log{a}$ or $\log_{10}{a}$.
Use the change-of-base formula above and a calculator to obtain:
\begin{align*}
\log_2{7}&=\dfrac{\log7}{\log2}\\
&\approx 2.8074
\end{align*}
