## Algebra: A Combined Approach (4th Edition)

$−5$
Step 1: $\sqrt −25×\sqrt -1$ Step 2: As $\sqrt -1=i$, the expression becomes $i\sqrt 25\times i$ Step 3: Since $i^{2}=-1$, the expression becomes $−\sqrt 25$ Step 4: Simplifying, the expression becomes $−5$