How do you insert absolute value equations into the TI-83 plus?

Use the abs( function. To get to it, press MATH, scroll over to NUM on the top, and choose abs(. Put what is in between the absolute value bars in parenthesis.

For example |X+3| would be abs(x+3).

Another example: 3|X-2| + 5 would be 3abs(X-2)+5.