If you can graph a function, you can graph piecewise functions. Each one of them is a different line or curve within the domain for that specific line of curve. If the domain states it's less than or greater than a number, you circle that point on the line. If the domain states it's also possibly equal to the point at the beginning or the end, you make a closed dot.
I"m sure that's clear as mud, please respond with any additional questions.