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Mathematics 23 Online
OpenStudy (ashy98):

help?

OpenStudy (ashy98):

OpenStudy (ashy98):

@e.mccormick @Abhisar @Help12356789

OpenStudy (e.mccormick):

Well, do you know what is needed to add or subtract radicals?

OpenStudy (ashy98):

no :

OpenStudy (e.mccormick):

It is like fractions. What is under needs to match. \(\dfrac{2}{x}\pm \dfrac{1}{y}\) can't be added or subtracted, but \(\dfrac{2}{x}\pm \dfrac{1}{x}\) can. Well, \(2\sqrt{x}\pm \sqrt{y}\) can't be added or subtracted, but \(2\sqrt{x}\pm \sqrt{x}\) can. The key is that what is under the fraction or under the radical matches. Your don't have matching things, but can one be changed so that they do match?

OpenStudy (ashy98):

okay so it would be B?

OpenStudy (e.mccormick):

It is like fractions. What is under needs to match. \(\dfrac{2}{x}\pm \dfrac{1}{y}\) can't be added or subtracted, but \(\dfrac{2}{x}\pm \dfrac{1}{x}\) can. Well, \(2\sqrt{x}\pm \sqrt{y}\) can't be added or subtracted, but \(2\sqrt{x}\pm \sqrt{x}\) can. The way to get things out from under a root is with prime factors. Take \(\sqrt{45}\) as an example. What do you get if you prime factor it? Well, 9*5=45, so \(\sqrt{9\cdot 5}\). But that is not prime factors. 3*3=9, so \(\sqrt{3\cdot 3\cdot 5}\) is using primes. Now, because this is a square root, you have to pull things out in pairs. If it was a cube root it would be in triples and so on. Now, there are a pair of threes. \(\sqrt{3\cdot 3\cdot 5}= 3 \sqrt{5}\) Hehe, and here I was working that up. What one was b? I did not leave it open.

OpenStudy (ashy98):

It is rational and equal to 0.

OpenStudy (e.mccormick):

Yah, that is the correct one.

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