Example  1
Evaluate the following.

  1. \(\left | 5 \right |\)

    \(\left | 5 \right | = 5 \), since \(\left | a \right | = a \) for \(a \ge 0\).

  2. \(\left | -12 \right |\)

    \(\left | -12 \right | = 12 \), since \(\left | a \right | = -a \) for \(a \lt 0\).