Partial Fraction Question: HELP with Polynomial Long Division

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SUMMARY

The discussion focuses on solving the rational expression (x^2 - x - 13)/((x^2 + 7)(x - 2)) using polynomial long division and partial fraction decomposition. Participants clarify that polynomial long division is unnecessary since the degree of the numerator is less than that of the denominator. The correct approach involves expressing the rational function as a sum of simpler fractions, specifically (2x + 3)/(x^2 + 7) - 1/(x - 2), which was confirmed by an online calculator. Proper notation, including parentheses, is emphasized for clarity in mathematical expressions.

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  • Understanding of polynomial long division
  • Familiarity with partial fraction decomposition
  • Knowledge of rational expressions
  • Basic algebraic manipulation skills
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  • Study polynomial long division techniques in detail
  • Learn about partial fraction decomposition methods
  • Practice decomposing various rational expressions
  • Review algebraic notation and the importance of parentheses in expressions
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Students studying algebra, particularly those tackling polynomial long division and partial fractions, as well as educators looking for step-by-step problem-solving techniques in rational expressions.

n31son
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Homework Statement



x^2-x-13/(x^2+7)(x-2)

hello i am having trouble solving this problem.. could anyone please show me how to do this step by step? i know polynomial long division is required before it can be converted to partial fractions.

I also know the answer is 2x+3/x^2+7 - 1/x-2 from an online calculator. but think I am missing something in the method to reach the answer.
any help appreciated thanks
 
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n31son said:

Homework Statement



x^2-x-13/(x^2+7)(x-2)
Unless you meant x2 - x - (13/(x2 + 7)(x - 2)), this should be written as (x^2-x-13)/((x^2+7)(x-2)).


n31son said:
hello i am having trouble solving this problem.. could anyone please show me how to do this step by step? i know polynomial long division is required before it can be converted to partial fractions.

I also know the answer is 2x+3/x^2+7 - 1/x-2 from an online calculator. but think I am missing something in the method to reach the answer.
I doubt that is the answer. Maybe you meant (2x + 3)/(x2 + 7) - 1/(x - 2). You should get in the habit of using parentheses around the numerator and denominator of your fractions.
n31son said:
any help appreciated thanks

No, you don't need to do polynomial long division first. The degree of the numerator is less than the degree of the denominator, so that division is unnecessary.

How did you break up the two fractions?
 


its defo the answer as it has been marked but returned for not showing working.
i may be wrong about the poly long division tho.
 


pf qu.jpg
 


What you show in post #4 is what you're starting with. When you decompose a rational expression such as that, you write it as a sum of two or more rational expressions.

For example, if you had to decompose x/(x2 - 4), you would write it as A/(x - 2) + B/(x + 2), and you would solve for the constants A and B.

How are you going to break up your rational expression?
 

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