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Absolute Value

For a real number, the absolute value of $$x$$, denoted $$\lvert x \rvert$$, is defined as

$\left|x \right| = \begin{cases} x, & \text{if } x \geq 0 \\ -x, & \text{if } x < 0. \end{cases}$

Working with absolute value often requires dealing with each of these cases separately. This can be clearly seen in the graph of the absolute value function $$y = \lvert x \rvert$$, where the slope of the line is 1 when $$x > 0$$ but is -1 when $$x < 0$$.

For example, to evaluate $$\left| 3\left( 17-55 \right) \right|$$:

\begin{align} \left| 3\left( 17-55 \right) \right| &= \left| 3\left( -38 \right) \right| \\ &= \left| -114 \right| \\ &= 114. \end{align}

Note by Arron Kau
2 years, 11 months ago

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