6.2.2 Fundamental Theorem of Algebra (continued) Example 3 Writing a Polynomial Function with Complex Zeros
The real numbers are a subset of the complex numbers, so every real number is also a complex number. A real number a can be written as the complex number a + 0 i . But here the term complex root will only refer to a root of the form a + bi , where b ≠ 0. Complex roots, like irrational roots, come in conjugate pairs. Recall that the complex conjugate of a + bi is a − bi . Complex Conjugate Root Theorem If a + bi is a root of a polynomial equation with real number coefficients, then a − bi is also a root.
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