Function
one- to -one
Step-by-step explanation:
For a relation to be a function, each of the input of the function must have only one output.
The input are the x values while the output are the y values.
Input -2 has one output of -1
input -1 has output of -2
input 0 has output 0
input 1 has output 2
input 2 has output 4
Each of the input have only one output.
Hence, it is a function
A function is one-to-one when the elements in the domain has one value in the range.
Hence, it is one-to-one