Question

The simplest form of $\sqrt{-18}\times \sqrt{-50}$ is

• A. $-30$
• B. $-30i$
• C. $30$
• D. $30i$

Answer 1

The correct option is A $-30$

We know that $i^2=-1$
So, $\sqrt{18i^2}\times \sqrt{50i^2}$
$=$ $i\sqrt{18}\times i\sqrt{50}$
$=$ $i^2\sqrt{18\times 50}$
$=$ $-\sqrt{900}$
$=-30$