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I got this question

Find the square root of $12+2\sqrt{6}$ expressing your answer in the form $\sqrt{m}+\sqrt{n}$.

I have no idea what this means and how to go about it.

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What is a surds? –  Euler....IS_ALIVE Feb 3 '13 at 23:02
    
@Euler....IS_ALIVE Are you serious with that question? –  Mob Feb 3 '13 at 23:04
    
Irrational root in American English. –  Mob Feb 3 '13 at 23:05
3  
It was a serious question. In 7 years of undergrad and graduate work, I've never seen that word. I googled it, but I am fairly confident that is an unusual word. Someone correct me if I'm wrong. –  Euler....IS_ALIVE Feb 3 '13 at 23:06
2  
@Euler....IS_ALIVE Quite usual, actually. –  1015 Feb 3 '13 at 23:07

1 Answer 1

up vote 5 down vote accepted

Let $x = \sqrt{12 + 2\sqrt{6}} = \sqrt{n} + \sqrt{m}$. Then $x^2 = 12 + 2\sqrt 6 = n + m + 2 \sqrt{nm}$.

Find $n$ and $m$ such that $n + m = 12$ and $nm = 6$.

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Can you expatiate on this? –  Mob Feb 3 '13 at 23:13
1  
Surdly you can solve the system of equations Damien has given. –  Euler....IS_ALIVE Feb 3 '13 at 23:18

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