10
practice testMultiple Choice

Practice Test

Question 10 • Algebra 2 with Probability

Find all solutions to the equation x cubed minus 4 x squared plus 9 x minus 10 is equal to 0

Answer
A
negative 10 comma 1 plus 2 i comma 1 minus 2 i
B
2 comma negative 1 plus 2 i comma negative 1 minus 2 i
C
2 comma 1 plus 2 i comma 1 minus 2 i
D
negative 2 comma negative 1 plus 2 i comma negative 1 minus 2 i

Explanation

Test the real roots suggested by the choices in the polynomial. Substituting x = 2 gives 8 − 16 + 18 − 10 = 0, so (x − 2) is a factor. Dividing x³ − 4x² + 9x − 10 by (x − 2) gives x² − 2x + 5, whose roots are x = (2 ± √(4 − 20))/2 = 1 ± 2i. The solutions are 2, 1 + 2i, and 1 − 2i, which is choice C.

AI-written and checked against the verified answer.

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