Polynomial Division: Simplifying 3rd Roots in Denominator

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SUMMARY

The discussion focuses on simplifying the expression \(\frac{ \sqrt[3]{25} + \sqrt[3]{5x} + \sqrt[3]{x^2} }{ \sqrt[3]{x} - \sqrt[3]{5} }\) by eliminating the cube roots from the denominator. The key technique recommended is using the identity \(y^3 - a^3 = (y - a)(y^2 + ay + a^2)\) to facilitate the simplification process. Participants emphasized the importance of recognizing this identity to effectively rewrite the expression without roots in the denominator.

PREREQUISITES
  • Understanding of cube roots and their properties
  • Familiarity with polynomial identities, specifically \(y^3 - a^3\)
  • Basic algebraic manipulation skills
  • Knowledge of rationalizing denominators
NEXT STEPS
  • Study the application of the identity \(y^3 - a^3\) in various algebraic contexts
  • Practice simplifying expressions with roots in the denominator using rationalization techniques
  • Explore polynomial long division and its applications in algebra
  • Learn about advanced algebraic identities and their proofs
USEFUL FOR

Students studying algebra, particularly those tackling polynomial expressions and simplification techniques, as well as educators looking for effective teaching methods in algebraic concepts.

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3rd roots in denominator

Homework Statement


[tex]\frac{ \sqrt[3]{25} + \sqrt[3]{5x} + \sqrt[3]{x^2} }{ \sqrt[3]{x} - \sqrt[3]{5} }[/tex]

Rewrite the expression with no roots in the denominator and it being simplified as far as possible.

Homework Equations


The Attempt at a Solution


I'm.. stumped. Seriously. How on Earth do I get rid of them? I can't do the conjugate, I can't take the denominator to the power of three, I can't take it times (x3 + 53) and I'm out of ideas.Sorry about it being called Polynomial division, mishap on my behalf.
 
Last edited:
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Try to use the identity

y3-a3=(y-a)(y2+ay+a2)

ehild
 
Thank you! I'd never have figured that one out myself
 

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