Which expression is not equal to 0?
5 - 5
-7+7
6-(-6)
-8-(-8)

Apatient is given 50 mg dose of medicine the medicines effectiveness decreases every hour at a constant rate of 40% what is the exponential decay function that models this scenario how much medicine will be left in the patients system after 2 hours

Ineed to know the answer to this algebra question.

How do the number line graphs of the solutions sets of -23 > x and x-23 differ?