Problem : Decide whether the graph below is a function.

Yes.

Problem : Decide whether the graph below is a function.

No.

Problem : Decide whether the graph below is a function.

No

Problem : What is the domain and range of the function f (x) = ?

Domain D: positive real numbers, range R: positive real numbers.

Problem : What is the domain and range of the function f (x) = ?

Domain D: real numbers ≠2. Range R: real numbers.

Problem : Is the following a function: y = ±x?

No.

Problem : Is the following a function: y = | x|?

Yes.