What value(s) must be excluded from the domain of f={(x,y): y=x+2/x-2}?

Question

Potential options are:

A. -2

B. 0

C. 2

D. 2 and -2

E. no value

Answer 1

With functions domains, I think it is helpful to consider what you CANNOT use (undefined or answers that are not real). For most functions there are two main concerns:

 1. you cannot have negative under a square root (or any "even radical")

2. you cannot have zero in the denominator

 

The answer for your problem is "C"