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Find the ordered pair (a,b) of real numbers for which x^2+ax+b has a non-real root whose cube is 1.

 Jun 9, 2022
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Let the root be z.

 

We have the equation: z3=1

 

Subtracting 1 from both sides gives: z31=0

 

Factoring out the left-hand side, we get: (z1)(z2+z+1)=0

 

Oh, look... It's a quadratic that so happens to be in the form ax2+bx+c=0

 

This means that the quadratic we are looking for is z2+z+1=0, so the ordered pair is (1,1)

 Jun 9, 2022

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