Up until now, you have known it was impossible to take a square root of a negative number. This is true when considering solutions that are only *real numbers*. But here you will learn about a new kind of number that lets you work with square roots of negative numbers! Complex numbers are made from both real and imaginary numbers. Imaginary numbers result from taking the square root of a negative number.

We will first define and perform algebraic operations on complex numbers; then we will provide examples of quadratic equations that have solutions that are complex numbers.