find all numbers whose absolute value is 7. if there is more than one, separate them with commas. if there…

Explanation:

Step1: Recall absolute - value definition

The absolute value of a number $x$, denoted as $|x|$, is defined as $|x|=\begin{cases}x, & x\geq0\ -x, & x < 0\end{cases}$. We want to find $x$ such that $|x| = 7$.

Step2: Solve for positive and negative cases

Case 1: If $x\geq0$, then $|x|=x$. Setting $x = 7$ satisfies $|x| = 7$ when $x$ is non - negative. Case 2: If $x<0$, then $|x|=-x$. Setting $-x = 7$, we get $x=-7$.

Answer:

$7,-7$