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1. How do you do Q2 on JAN 11 CORE 1 OCR?

http://www.ocr.org.uk/Images/65379-q...hematics-1.pdf

Please explain in detail, I've look at previous explanations and I don't get it!
2. Well I do not know which explanations you have not understood. However since it is an identity (true for all x).
Substitute in x=0 to get 5p=2q and also some other value of x to get another equation.

If you factorise both sides fully you find a common factor of (x+2) on both sides which cancels to give (x-p)(2x+5)=(x-2)(2x+q) which makes life easier.
Once you sub in x=2, the RHS is zero and the LHS is fairly easy.

Next use x=-5/2 which makes the LHS zero and the RHS fairly easy

The key point is knowing what an identity is. You can put in any value of x you like and choosing a sensible value will give you a relatively straightforward thing to do.

3. Here is a detailed look at a simple version of what the mark scheme wants.
First factorise both sides to give

We can divide out the (x+2) to get
(if you don't get this divide out of (x+2) life is just harder but it will work out.
and multiply both sides out to get

Compare coefficients of to get
Compare coefficients of to get
Hence we can solve the pair of SEs to get p=2 and q=5

If you miss dividing out the (x+2) then you get a cubic on each side but it still works out.

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