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flynno37
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pike
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flynno37
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Thank you for your responses so far. I think I am having difficulty in the application of the FOIL rule.
Here is how I am using FOIL to expand the equation. Can anyone pinpoint where I am going wrong?

(√(〖3-2x〗^ ))₂ = (√2x+1)₂ Square both sides
3-2x = 2x + √2x+1

So, I am doing this:
(√2x+1)₂ = (√2x+1) (√2x+1)
F (first): √2x √2x

O (outer): √2x +1

I (Inside): +1 √2x

L (last): + 1 + 1

Can anyone explain what I do next?
This may be a silly question but should I multiply each result of doing FOIL?
So the result of F (first) will be √4x₂ ?
And √2x multiplied by +1 will just be √2x?
Or is it more of a case of connecting the components? As I have done above.
Is it correct to be able to connect the √2x (in O) with the √2x (in I)? So that will be 2 √2x ?

I am trying not to get hung up on this but I have been told it’s pretty fundamental to get it!

Any general recommendations would be appreciated!

Thank you,

Sorry for the formatting. I'm pasting in from ms word.
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Yep it is fundamental, so its good you are making sure you understand it!

Take each component and add them together (so add F + O + I + L). Then you have fully expanded the equation out of brackets.

What books are you using? I just did some quick google searches, there are tons and tons of guides and videos that may be helpful.

I can't vouch for any, but check out:

https://www.youtube.com/watch?v=iw-sC9uHjPg
https://www.youtube.com/watch?v=qgtUXG4r_wM
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flynno37
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Thanks for your help. I think I have it now.

The books I'm using are:

Official guide for GMAT review, 12th edition
Kaplan GMAT math workbook
AS Level Mathematics (Text book from UK high school)

Do you recommend taking the Kaplan courses or others that are paid classroom / online packages?
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pike
Some strange formatting in your question makes it a little difficult to understand what is going on. Might want to use the formatting tags to make a little clearer. My expansion looks like:

\((\sqrt{2x} + 1)^2\)

\((\sqrt{2x} + 1)^2 = (\sqrt{2x} + 1)(\sqrt{2x} + 1)\)

\((\sqrt{2x} + 1)^2 = \sqrt{2x}\sqrt{2x}+2\sqrt{2x} + 1\)

\((\sqrt{2x} + 1)^2 = 2x + 2\sqrt{2x} + 1\)

\((\sqrt{2x} + 1)^2 = 2(x + \sqrt{2x}) + 1\)

What software are you using to do the maths? It makes equations look good :)
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