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# Help me! Please! haha watch

1. how do i solve this:

I know to get B we let x=1 and solve to get B=1/3

But to get A and C do we have to equate coefficients?

Would equating x terms give: -A + B - 2C = 0 ?
and then equating constant terms: A + 2B + C = 1

then we add the two to remove the x term then sub 1/3 in for B to allow us to get C.

But I get that C=0?

How can this be? What have i done wrong?
2. (Original post by Mr Tall)
how do i solve this:

I know to get B we let x=1 and solve to get B=1/3

But to get A and C do we have to equate coefficients?

Would equating x terms give: -A + B - 2C = 0 ?
and then equating constant terms: A + 2B + C = 1

then we add the two to remove the x term then sub 1/3 in for B to allow us to get C.

But I get that C=0?

How can this be? What have i done wrong?
c has to be zero as c(1-x)^2 is the only term which has an x^2.
3. (Original post by steve44)
c has to be zero as c(1-x)^2 is the only term which has an x^2.
why does this mean it has to be zero? thanks
4. Expand out the brackets and equate x^2 terms.

5. becomes

In answer to your question about whether equating x terms gives -A + B -2C = 0 and equating constant terms gives A + 2B + C = 1... this is correct. Plus as there is no x^2 term on the RHS we can just immediately conclude C = 0.

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Updated: January 20, 2014
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