SOLUTION: Verify that P(x) = x^3 - x^2 - ix^2 - 20x + ix + 20i has a zero of i and that its conjugate -i is not a zero. Explain why this does not contradict the Conjugate Pair Theorem.

Question 57257This question is from textbook Applied College Algebra
: Verify that P(x) = x^3 - x^2 - ix^2 - 20x + ix + 20i has a zero of i and that its conjugate -i is not a zero. Explain why this does not contradict the Conjugate Pair Theorem. This question is from textbook Applied College Algebra

Answer by Scriptor(36) (Show Source): You can put this solution on YOUR website!
Just fill in i in your function and check if it becomes 0.
Make use of the property that i� = -1
P(i) = i� - i� -i*(i�) -20i + i*i + 20i
= -i + 1 + i - 20i - 1 + 20i
= 0
Check for yourself that P(-i) is NOT equal to zero (same mehod as above)
This does not contradict the Conjugate Pair Theorem, because not all the coefficients of P(x) are real.
Greets,
Scriptor
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