SOLUTION: I don't understand how (n-2)/(n^3-8) becomes 1/(n^2+2n+4). I get how you take out the common factor of (n-2), but why does the denominator become n^2+2n+4 instead of n^2+4?

Algebra ->  Polynomials-and-rational-expressions -> SOLUTION: I don't understand how (n-2)/(n^3-8) becomes 1/(n^2+2n+4). I get how you take out the common factor of (n-2), but why does the denominator become n^2+2n+4 instead of n^2+4?      Log On


   



Question 946254: I don't understand how (n-2)/(n^3-8) becomes 1/(n^2+2n+4).
I get how you take out the common factor of (n-2), but why does the denominator become n^2+2n+4 instead of n^2+4?

Found 2 solutions by Alan3354, MathTherapy:
Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
I don't understand how (n-2)/(n^3-8) becomes 1/(n^2+2n+4).
I get how you take out the common factor of (n-2), but why does the denominator become n^2+2n+4 instead of n^2+4?
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(n-2)*(n^2+4) = n^3 - 2n^2 + 4n - 8
----
That's <> n^ - 8

Answer by MathTherapy(10551) About Me  (Show Source):
You can put this solution on YOUR website!
I don't understand how (n-2)/(n^3-8) becomes 1/(n^2+2n+4).
I get how you take out the common factor of (n-2), but why does the denominator become n^2+2n+4 instead of n^2+4?

%28n+-+2%29%2F%28n%5E3+-+8%29
%28n+-+2%29%2F%28%28n+-+2%29%28n%5E2+%2B+2n+%2B+4%29%29 ----- Factoring denominator
cross%28%28n+-+2%29%29%2F%28cross%28%28n+-+2%29%29%28n%5E2+%2B+2n+%2B+4%29%29 ---- Cancelling n - 2 in numerator and denominator
highlight_green%281%2F%28n%5E2+%2B+2n+%2B+4%29%29