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What is the complete factorization of the polynomial below?

x^3 + 2x^2 + x + 2
A. (x-2)(x+ i)(x + i)
B. (x-2)(x + i)(x - i)
C. (x + 2)(x + i )(x- i)
D. (x + 2)(x + i )(x + i)

User Truezplaya
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1 Answer

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The complete factorization of the polynomial, x³ + 2·x² + x + 2, obtained by finding the zeros of the polynomial is; (x + 2)·(x + i)·(x - i), which corresponds to option D

D. (x + 2)·(x + i)·(x - i)

What is a polynomial?; A polynomial consists of coefficients of variables, raised to positive integer powers, and mathematical operators, including addition subtraction and multiplication

The cubic function x³ + 2·x² + x + 2 can be factorized as follows;

When x = -2, we get;

(-2)³+ 2×(-2)² + (-2) + 2 = 0, therefore; (x + 2) is a factor of the cubic expression, x³ + 2·x² + x + 2

The division of x³ + 2·x² + x + 2 by (x + 2), indicates that we get;

x² + 1

(x + 2)| x³ + 2·x² + x + 2

x³ + 2·x²

x + 2

x + 2

0

Therefore, the factors of 2·x² + x + 2 are (x + 2) and (x² + 1)

Where x² + 1 = 0, we get;

x = √(-1)

The value √(-1) is √(-1) = i which is a complex number

x = i, therefore (x - i) is a factor of x² + 1, and we get;

(x² + 1) = (x + i) × (x - i)

2·x² + x + 2 = (x + 2) × (x² + 1)

2·x² + x + 2 = (x + 2) × (x + i) × (x - i)

The option D is correct

User Leland
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