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

$9i$
Step 1: $\sqrt 27\times\sqrt -3$ Step 2: $\sqrt (27\times-3)$ Step 3: $\sqrt (-81)$ Step 4: $\sqrt -1\times\sqrt 81$ Step 5: As $\sqrt -1=i$, the expression becomes $i\sqrt 81$ Step 6: Simplifying further, the expression becomes $i(9)$ or $9i$