Chapter 8 - Section 8.3 - Polar Form of Complex Numbers; De Moivre's Theorem - 8.3 Exercises - Page 609: 1

A complex number $z=a+bi$ has two parts: $a$ is the real part, and b is the imaginary part. To graph $a+bi$, we graph the ordered pair $a, b$ in the complex plane.

This comes directly from the definition of "complex number" on page 59 as well as the section "Graphing Complex Numbers" on page 602.