Answer
-2.3219
Work Step by Step
From the change of base formula, we know that $log_{b}a=\frac{log_{c}a}{log_{c}b}$ ($a$, $b$, and $c$ are positive real numbers and neither $b$ nor $c$ is equal to 1).
Therefore, $log_{\frac{1}{2}}5=\frac{log_{10}5}{log_{10}\frac{1}{2}}=\frac{0.6990}{-0.3010}=-2.3219$.