# Math Help - square root question

1. ## square root question

Good Day,

Just wanted to ensure i did this question correctly, the question was to write the problem below in standard form. If incorrect any help to solve this question would be appreciated.

2. Hello, netlab!

Your steps seem to be okay, but that $\sqrt{1}$ is unnecessary.

$5\sqrt{\text{-}16} \:+ \:3\sqrt{\text{-}81}$

. . $= \;5\sqrt{(16)(\text{-}1)} \:+ \:3\sqrt{(81)(\text{-}1)}$

. . $= \;5\!\cdot\!\sqrt{16}\!\cdot\!\sqrt{\text{-}1} \:+ \:3\!\cdot\!\sqrt{81}\!\cdot\!\sqrt{\text{-}1}$

. . $= \;5\!\cdot\!4\!\cdot\!i \:+\: 3\!\cdot\!9\!\cdot\!i$

. . $=\;\;20i + 27i \;\;=\;\;\boxed{47i}$

3. Ok, thanks a lot for your help