Evaluate square root of -144

$\sqrt{- 144}$

Step 1

Rewrite $- 144$ as $- 1 (144)$ .

$\sqrt{- 1 (144)}$

Step 2

Rewrite $\sqrt{- 1 (144)}$ as $\sqrt{- 1} \cdot \sqrt{144}$ .

$\sqrt{- 1} \cdot \sqrt{144}$

Step 3

Rewrite $\sqrt{- 1}$ as $i$ .

$i \cdot \sqrt{144}$

Step 4

Rewrite $144$ as $12^{2}$ .

$i \cdot \sqrt{12^{2}}$

Step 5

Pull terms out from under the radical, assuming positive real numbers.

$i \cdot 12$

Step 6

Move $12$ to the left of $i$ .

$12 i$