Final answer:
Complex conjugate pairs are always roots of a polynomial with real coefficients.
Step-by-step explanation:
Given that 1 + 2i is a zero of the function f(x) = x^2 - 2x + 5, we can conclude that 1 - 2i is also a zero.
This is because complex conjugate pairs are always roots of a polynomial with real coefficients. In other words, if a + bi is a root of a polynomial, then a - bi is also a root.
Since the given polynomial f(x) = x^2 - 2x + 5 has real coefficients, the complex conjugate of 1 + 2i, which is 1 - 2i, is also a root of the polynomial.