Is [math](12 – i^{20}) + (–18 – 4i^{18})[/math] wholly real or wholly imaginary, or does it have both a real and an imaginary part?

[list=1][br][*]Simplify any expressions containing [math]i^n[/math].[br][*]Find the sum or difference of the real parts.[br][*]Find the sum or difference of the imaginary parts.[br][*]Find the sum of the real and imaginary parts.[br][*]Use the form of the sum to determine if it is wholly real or wholly imaginary, or if it has both a real and an imaginary part.[br][/list][br][br]This applet is provided by Walch Education as supplemental material for their mathematics programs. Visit [url="http://www.walch.com"]www.walch.com[/url] for more information on their resources.