Question

Using the given zero, find one other zero of f(x). Explain the process you used to find your solution. 1 - 2i is a zero of f(x) = x4 - 2x3 + 6x2 - 2x + 5.

Answer 1

SInce one of the zeros is 1 - 2i, another zero has to be 1 + 2i.
You get a complex zero by taking the square root of a negative number, When you take the square root of a number you get two answers (unless you are taking the square root of zero).
In order to get -2i you had to be taking the sqrt (-4) which is + - 2i