How do you simplify #abs(33)#?
The absolute value function is a special class of function called a piecewise function. What this means is it has more than one definition that depends on the input.
Those definitions are:
so for our example
The above is the technical definition of the function. However, I think it is easier to think about it as a distance function. The absolute value tell you how far a number is from zero. Then it becomes obvious what the value should be.
and this is simplification makes us happy.