Question

Which expression does not belong with the other three? explain your answer

Answer 1

-6 is the expression that doesn't belong because it's the only true negative number. Absolute value signs (||) indicate that the number will be positive, even if it has a negative sign. So, 6, |6|, and |-6| are all equal. 

Answer 2

The Modulus of a Number ,P or -P, and , if you take positive Sign behind that number , that is +P, these three are equivalent real numbers.

That is

|P|=|-P|=+P

So, |6|=6=|-6|≠ -6

⇒ -6, does not belong to other three, that is ,|6|, 6 and |-6|.

Option C= -6