Question

describe the error. What should the answer should've been?how did they get the wrong answer?

Answer 1

An absolute value is a distance, then, all the numbers that are absolute values are possitive, as a distance cannot be negaive:

Then,

$\begin{gathered} \mleft|-x\mright|=x \\ \mleft|-8\mright|=8 \end{gathered}$Then, the mistake is that the absolute value of -8 is 8 not -8The absolute value of a negative number is the number but possitive.