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# C3 Rational Expression question

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Why bother with a post grad course - waste of time? 17-10-2016
1. Hi can someone explain how to do this please?

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2. Hope that helps, jessyjellytot14
3. (Original post by jessyjellytot14)
Hi can someone explain how to do this please?

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You can multiply both sides of the identity by (x+3) then proceed to expand and compare coefficients in terms of A and B because they must be the same on both sides of the identity.
4. (Original post by RDKGames)
You can multiply both sides of the identity by (x+3) then proceed to expand and compare coefficients in terms of A and B because they must be the same on both sides of the identity.
Okay I tried multiplying each side by (x+3) but i'm not sure if you meant like this...

When I compare the coefficients I just end up with 2x+5/x+3 again or something that is not on the mark scheme

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5. (Original post by jessyjellytot14)
Okay I tried multiplying each side by (x+3) but i'm not sure if you meant like this...

When I compare the coefficients I just end up with 2x+5/x+3 again or something that is not on the mark scheme

Posted from TSR Mobile
You multiplied the denominator by (x+3), no need to do that. Just multiply both sides of the identity by the denominator of the LHS so you can lose it.
6. (Original post by RDKGames)
You multiplied the denominator by (x+3), no need to do that. Just multiply both sides of the identity by the denominator of the LHS so you can lose it.
Okay thanks- Once you have the quotient and remainder, can you write it in the form: Quotient + Remainder/ x+3 ?
7. (Original post by jessyjellytot14)
Okay thanks- Once you have the quotient and remainder, can you write it in the form: Quotient + Remainder/ x+3 ?
When you find your values of A and B then yeah, just plug them into identity.

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