SOLUTION: Write a polynomial function with rational coeffecients so that P(x)=0 has the given roots. -5 and 3i

Algebra ->  Polynomials-and-rational-expressions -> SOLUTION: Write a polynomial function with rational coeffecients so that P(x)=0 has the given roots. -5 and 3i      Log On


   

Question 390320: Write a polynomial function with rational coeffecients so that P(x)=0 has the given roots.
-5 and 3i
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
Write a polynomial function with rational coeffecients so that P(x)=0 has the given roots.
-5 and 3i
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If it has rational coefficients -3i must also be a root.
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(x+5)(x-3i)(x+3i) = 0
(x+5)(x^2+9) = 0
x^3 + 5x^2 + 9x + 45 = 0
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Cheers,
Stan H.
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