What is the common root for two polynomial equations with a shared coefficient?

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Homework Help Overview

The problem involves finding the value of 'a' for which the polynomial equations x³ + ax + 1 = 0 and x⁴ + ax + 1 = 0 share a common root. Participants are exploring the implications of this shared root in the context of polynomial equations.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants discuss the approach of subtracting the two equations to find a common root and express uncertainty about the effectiveness of this method. There are questions regarding the validity of the derived value of 'a' and the correctness of the given answer.

Discussion Status

The discussion is ongoing, with participants sharing their attempts and questioning the accuracy of the provided answer. Some guidance has been offered regarding the need to verify assumptions and seek consensus on the findings.

Contextual Notes

There is a noted discrepancy between the calculated value of 'a' (-2) and the answer given in the problem (-1), leading to further questioning of the assumptions and methods used in the calculations.

vijayramakrishnan
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Homework Statement


[/B]
Th value of 'a' for which the equation x3+ax+1=0 and x4+ax+1=0 have a common root is?

Homework Equations

The Attempt at a Solution



i initially thought of subtracting both the equations and then finding x and substituting back in the equation but it did not work.
 
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vijayramakrishnan said:

Homework Statement


[/B]
Th value of 'a' for which the equation x3+ax+1=0 and x4+ax+1=0 have a common root is?

Homework Equations

The Attempt at a Solution



i initially thought of subtracting both the equations and then finding x and substituting back in the equation but it did not work.
Please show how you did it, and why it did not work.
What you write seems to be the way to go.
 
Samy_A said:
Please show how you did it, and why it did not work.
What you write seems to be the way to go.
Samy_A said:
Please show how you did it, and why it did not work.
What you write seems to be the way to go.
thank you for replying sir
subtracting we get x4-x3=0
x can be 1 or 0.
substituting back in the equation we get a = -2
but answer given is -1.
 
vijayramakrishnan said:
thank you for replying sir
subtracting we get x4-x3=0
x can be 1 or 0.
substituting back in the equation we get a = -2
but answer given is -1.
a = -2 : looks correct to me.
 
Samy_A said:
a = -2 : looks correct to me.
than you sir for replying
then answer must be wrong,sorry for wasting your time
 
vijayramakrishnan said:
than you sir for replying
then answer must be wrong,sorry for wasting your time
No need to apologize: when a given answer looks wrong (something that can happen), the best you can do is ask to see if others agree.
 
Samy_A said:
No need to apologize: when a given answer looks wrong (something that can happen), the best you can do is ask to see if others agree.
yes sir thank you very much
 

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