Absolute value of a variable, say x, is simply whatever you put in as a number for x say -3 it becomes positive. It looks like this |x| . So y = |x| . If x is -5 then y is 5. If x is 10 then y is 10. If x is -20 then y is 20. You get the idea. You simply make sure whatever is inside the brackets comes out positive.

Here's one more. y = | 5x - 10| ... Lets say x = -1. What is y?

| 5(-1) - 10 | = | -5 - 10 | = |-15| = 15

**Further discussion....**
If you had a number line - 10 to 0 and 0 to 10 and you wanted to find the distance from from 0 to -3 the distance would not be -3 its just 3 or | 0 - 3 | = | - 3 | = 3