What is the exact value of the expression sqrt(189) - sqrt(21) + sqrt(84) ? Simplify if possible.

Question

dumbsearch2 · Answer

I say it's 0.
And that's an understatement.

anonymous · Answer

I have multiple choice, you want the answers?

dumbsearch2 · Answer

I'll post them for you.

dumbsearch2 · Answer

a √ 21
b 6 √ 7
c4√ 21
d24√ 7

dumbsearch2 · Answer

The answer is


sqrt(189) - sqrt(21) + sqrt(84) =
sqrt(9 * 21) - sqrt(21) + sqrt(4 * 21) =
3 * sqrt(21) - sqrt(21) + 2 * sqrt(21) =
4 * sqrt(21)

dumbsearch2 · Answer

Thanks to http://answers.yahoo.com/question/index?qid=20101226103625AAFvk0a Cheater. geez. Don't go there for the rest of the answers. It's just not right.

dumbsearch2 · Answer

But give me a medal.
Because you can.
Click dat best answer button.

anonymous · Answer

Yay!! I guessed right