If you're referring to the different sets of real numbers, it's the ones that you could try to do subtraction and not get an answer that still in that set.
For example, natural numbers (aka 1, 2, 3, 4, ...) are not, because 7 - 11 = -4 and -4 is not a natural number.
Also, whole numbers (aka 0, 1, 2, 3, 4, ...) has the same issue.
Basically any set of real numbers that doesn't include negative numbers will have this issue.
Answer: B) f(x)= 1/5 |x|
Used graphic calculator
Answer:
Brainly is a platform that is used to help students in need. There are many social networks that offer socializing with many people from every country in the world.
I suggest you install any of those apps, and try find someone to talk to.
On this platform, we offer knowledge and help when it comes to important tests, quizzes and other knowledge-related topics.
Hope I helped.