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Example

Evaluating x|x|, y|-y|, and u-|u| for Given Values

When an absolute value expression contains a variable, substitute the given value and then apply the absolute value. Pay close attention to whether a negative sign sits inside or outside the absolute value bars, because the placement determines the sign of the result.

Inside the bars — always non-negative:

  • x|x| when x=35x = -35: Substitute to get 35|-35|. Since 35{-35} is 35{35} units from zero, 35=35|-35| = 35.
  • y|-y| when y=20y = -20: Substitute to get (20)|-(-20)|. Simplify the double negative: (20)=20=20|-(-20)| = |20| = 20.

Outside the bars — always non-positive:

  • u-|u| when u=12u = 12: Substitute to get 12-|12|. The absolute value gives 12{12}, then the outside negative makes it 12{-12}.
  • p-|p| when p=14p = -14: Substitute to get 14-|-14|. The absolute value gives 14{14}, then the outside negative makes it 14{-14}.

Notice: The expression variable-|\text{variable}| is the negative (opposite) of a distance, so it is always zero or negative — the outside minus sign is never "absorbed" by the absolute value bars.

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Updated 2026-04-21

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