Long Division of cubic polynomial

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Homework Help Overview

The discussion revolves around performing long division of cubic polynomials, specifically dividing the polynomial \(x^3+x^2-5x+3\) by \(x^3-3x+2\). Participants are exploring the implications of the missing \(x^2\) term in the divisor.

Discussion Character

  • Exploratory, Assumption checking

Approaches and Questions Raised

  • The original poster attempts to set up the long division but encounters difficulty due to the absence of the \(x^2\) term in the divisor. They question whether to represent the divisor with a zero coefficient for the \(x^2\) term. Other participants confirm this approach and suggest visualizing the polynomial with the missing term included.

Discussion Status

The discussion is active, with participants clarifying the setup of the long division process. Some guidance has been provided regarding how to represent the missing exponent, but no consensus on the overall method has been reached.

Contextual Notes

There is mention of alternative methods such as factoring and synthetic division, which may not align with the requirement to show full long division. Participants are navigating the constraints of the homework assignment while discussing different approaches.

LearninDaMath
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Homework Statement



\frac{x^3+x^2-5x+3}{x^3-3x+2}

Homework Equations





The Attempt at a Solution




well I'm drawing that long division house with x^3-3x+2 on the outside and x^3+x^2-5x+3 on the inside.

I'm seeing that x^3 goes into x^3 one time, so i put a 1 on top of the "house." then I multiply the 1 by x^3-3x+2 and put the product underneath x^3+x^2-5x+3 . However, I can't subtract or add the numbers because the exponents of the x variables don't line. I'm having a problem with the fact that x^3-3x+2 skips the x^2 exponent. I never did a long division problem where the outstide number skipped an exponent. Should I just make a space like x^3+0-3x+2 and let the x^2 from x^3+x^2-5x+3 drop down - kind of like what i would do if the number under the house x^3+x^2-5x+3 skipped a variable?
 
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"Should I just make a space like x^3+0-3x+2"
Yes, basically - a better way to visualize it might be
x^3+0x^2-3x+2
 
Appreciate it. Much thanks on the clarification.
 
LearninDaMath said:

Homework Statement



\frac{x^3+x^2-5x+3}{x^3-3x+2}

Homework Equations





The Attempt at a Solution




well I'm drawing that long division house with x^3-3x+2 on the outside and x^3+x^2-5x+3 on the inside.

I'm seeing that x^3 goes into x^3 one time, so i put a 1 on top of the "house." then I multiply the 1 by x^3-3x+2 and put the product underneath x^3+x^2-5x+3 . However, I can't subtract or add the numbers because the exponents of the x variables don't line. I'm having a problem with the fact that x^3-3x+2 skips the x^2 exponent. I never did a long division problem where the outstide number skipped an exponent. Should I just make a space like x^3+0-3x+2 and let the x^2 from x^3+x^2-5x+3 drop down - kind of like what i would do if the number under the house x^3+x^2-5x+3 skipped a variable?

In this case, the quickest method to do it is as follows: factorise the denominator. There's a linear factor in common between numerator and denominator. Divide the numerator by that factor using a shortcut like Ruffini's synthetic division (should be in the tutorials section, I think, if not, google it). After you do that, divide the resulting quadratic by other factor using Ruffini's method again and get the quotient and remainder.

If you're really required to show the full long division, you have no choice, but if you just need a quick result, the above is a fast and accurate method.
 

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