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C3 Algebraic fractions

In the attachment below this is given
(in the "where things can go ugly" section)
Blindly multiplying the two denominators when there might be a common factor, e.g. (𝑥+3)(𝑥−3) and (𝑥+3) should become (𝑥+3)(𝑥−3) rather than (𝑥+3)²(𝑥−3).

But surely multiplying
(x+3)(x-3) by (x+3) would give (x-3)²(x-3)????
(edited 7 years ago)
Reply 1
If you're adding 2 fractions, say A(x+3)(x3)+Bx+3\frac{A}{(x+3)(x-3)} + \frac{B}{x+3} then you're going to end up with A(x+3)+B(x+3)(x3)x+3x3x+3\frac{A(x+3)+B(x+3)(x-3)}{x+3}{x-3}{x+3} which is unnecessary because there's a common factor of (x+3) in the fraction. So it just ends up as
Unparseable latex formula:

\frac{A+B(x-3)}{(x+3)(x-3)




fml.. Latex is broken at the moment I think.

edit:
(edited 7 years ago)
Reply 2
Original post by Parallex
If you're adding 2 fractions, say A(x+3)(x3)+Bx+3\frac{A}{(x+3)(x-3)} + \frac{B}{x+3} then you're going to end up with A(x+3)+B(x+3)(x3)x+3x3x+3\frac{A(x+3)+B(x+3)(x-3)}{x+3}{x-3}{x+3} which is unnecessary because there's a common factor of (x+3) in the fraction. So it just ends up as A+B(x3)(x+3)(x3)\frac{A+B(x-3)}{(x+3)(x-3)}


fml.. Latex is broken at the moment I think.

edit:


But the question is ....
oh i forgot the definition of denominator xD silly me thanks anyway :smile:

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