Answer:
f(x) = x^3 + 2x^2 + x + 2
Step-by-step explanation:
If -2 + i is a zero, then -2 - i must also be a zero.
These zeros are -2, -2 + i and -2 - i, and the corresponding factors of the polynomail f(x) are (x + 2), (x + 2 - i) and (x + 2 + i).
(x + 2 - i) and (x + 2 + i) multiplied together becomes x^2 + 1.
Multiplying this result by the 3rd and last factor, (x + 2), we get
(x^2 + 1)(x + 2) = x^3 + 2x^2 + x + 2
Check, using synthetic division. What are the factors of x^3 + 2x^2 + x + 2?
-2 / 1 2 1 2
-2 -2 -2
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1 0 -1 0 Since the remainder is zero, we know that
(x + 2) is a factor and -2 is a root.
