Question

What is the value of the expression |a + b| + |c| when a = –3, b = 7, and c = –15?

Answer 1

We know:
$|a|= \left\{\begin{array}{ccc}a&if\ a \ \textgreater \ 0\\0&if\ a=0\\-a&if\ a \ \textless \ 0\end{array}\right\\\\|2|=2\\|0|=0\\|-3|=3$

$|a+b|+|c|$
substitute a = -3; b = 7; c = -15
$|-3+7|+|-15|=|4|+15=4+15=19$