i need to add 5 square root (7) and 3 square root (28). i can't figure out how to do it. please help me!!!!!

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- May 2nd 2008, 04:38 PMEmmGeeAdding Square Roots
i need to add 5 square root (7) and 3 square root (28). i can't figure out how to do it. please help me!!!!!

- May 2nd 2008, 04:56 PMblair_alane
First of all, the square root of 28= sq.root(7*4).....so it is also equal to 2 square root 7....so... 3 root 28 = 6 root 7.

so, 5 square root 7 + 6 square root 7 = 11 square root 7.

I dont know if my math is correct, but you just have to simplify your square roots.

Sorry for the sloppy math.... - May 2nd 2008, 05:01 PMJhevon
- May 2nd 2008, 05:02 PMMathnasium
In general, you can break square roots apart - for example, $\displaystyle \sqrt{44} = \sqrt{4}\times\sqrt{11}$. Of course, the square root of 4 is 2, so you get $\displaystyle 2\sqrt{11}$.

When you look to break apart larger numbers under a square root sign, you want to try to break them up into two factors where one of the factors is a perfect square (4, 9, 16, ...). - May 2nd 2008, 05:12 PMblair_alane
yes! the first one I got right! :D here...I'll write it again...

$\displaystyle 28=\sqrt(7*4)$.....so it is also equal to $\displaystyle 2\sqrt7$....so...

$\displaystyle 3\sqrt28=3*2\sqrt7=6\sqrt7$

so, $\displaystyle 5\sqrt7+6\sqrt7=11\sqrt7$

is that somewhat less confusing? (i found out how to do latex! teehee) I probably just made it worse! sorry! I dont know how to lay it out....

hope that helps! :) - May 2nd 2008, 05:15 PMblair_alane
- May 2nd 2008, 05:19 PMJhevon
type [tex]\sqrt{Anything}[/tex] to get $\displaystyle \sqrt{Anything}$.

so it would look nicer if you had $\displaystyle \sqrt{7 * 4}$ or better yet $\displaystyle \sqrt{7 \cdot 4}$ ..........use \cdot to get the dot. so the last one we got by typing [tex]\sqrt{7 \cdot 4}[/tex] - May 3rd 2008, 08:16 AMblair_alane