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# Help with question watch

1. So this question has been really getting me, I know the answer is the first option but am wondering how to work that out, could anyone show me? Thank you!
2. You just rationalize the denominator so multiply top and bottom by:

So:

Attachment 575898575902

Hope this helps
Attached Images

3. (Original post by hischebioict)

So this question has been really getting me, I know the answer is the first option but am wondering how to work that out, could anyone show me? Thank you!
You need to know the rule "difference between two squares" it is (a+b)(a-b)=a2-b2
Attached Images

4. (Original post by AlexJT)
You just rationalize the denominator so multiply top and bottom by:

So:

[WORKING OUT]

Hope this helps
Let's try and not do the question for the person. You can point him to what needs to be done just don't spoil it.

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Updated: August 27, 2016
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