Solve the inequality....and justify your answer

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Discussion Overview

The discussion revolves around solving the inequality 12x^3 + 8x^2 ≤ 3x + 2 and justifying the solution. Participants explore methods for addressing third-degree polynomials, including the use of the Rational Root Theorem and the creation of sign charts.

Discussion Character

  • Homework-related
  • Mathematical reasoning
  • Technical explanation

Main Points Raised

  • Some participants suggest solving the corresponding equality first as a step in addressing the inequality.
  • There is mention of taking the derivative and finding its roots as part of the solution process.
  • Participants discuss the need for a sign chart to interpret the results of the polynomial.
  • The Rational Root Theorem is proposed as a method to find the roots of the polynomial.
  • Clarifications are made regarding the terminology, specifically correcting "sin chart" to "sign chart."
  • There is an emphasis on rearranging the inequality to bring everything to one side before finding the roots.

Areas of Agreement / Disagreement

Participants generally agree on the steps to approach the problem, including the use of the Rational Root Theorem and the importance of a sign chart. However, the discussion remains unresolved regarding the specific methods and justifications needed for the inequality.

Contextual Notes

The discussion does not resolve the specific mathematical steps required to solve the inequality, and there are varying interpretations of the justification process.

Raerin
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Solve the inequality 12x^3 + 8x^2 ≤ 3x + 2 and justify your answer.

To justify the answer do you need to make a sin chart and graph it?
 
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How do you solve third degree polynom? Do you know what rational root Theorem is?
 
Raerin said:
Solve the inequality 12x^3 + 8x^2 ≤ 3x + 2 and justify your answer.

To justify the answer do you need to make a sin chart and graph it?

Hi Raerin! :)

The usual approach is to first solve the equality.
Then take the derivative and find its roots.
Then you can make a sign chart to read off the solution (did you mean a sign chart instead of a sin chart?)

The first step is already not so easy for this particular problem.
As Petrus suggested, the easiest way to find the roots is by using the Rational root theorem.
Do you know of it?
 
I like Serena said:
Hi Raerin! :)

The usual approach is to first solve the equality.
Then take the derivative and find its roots.
Then you can make a sign chart to read off the solution (did you mean a sign chart instead of a sin chart?)

The first step is already not so easy for this particular problem.
As Petrus suggested, the easiest way to find the roots is by using the Rational root theorem.
Do you know of it?
Oops, I made a typo, so yes, I do mean sign chart.
You're supposed to bring everything to one side, right? Then you find the number that would make the polynomial = 0?
 
Raerin said:
Oops, I made a typo, so yes, I do mean sign chart.
You're supposed to bring everything to one side, right? Then you find the number that would make the polynomial = 0?

Yep!
 

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