The given relation is:
{ (B,1) (2,3) (4,5) }
The domain, X = {B, 2, 4}
The range, Y = {1, 3, 5}
The domain is a set of all the input values
The range is a set of all the output values
Note that:
A relation is a function if every value of the domain (X) is attached to only one value of the range (Y)
A) For the relation to be a function, B can be any value except 2 and 4,
B = All real numbers except 2 and 4
B) The values of B that could create a relation only are 2, 4
This is because, for B = 2, 4, a value of X will be matched with more than one value of Y
A diagram showing the function is shown below:
The above is a function because every value of X is attached to just one value of Y. And for this to happen, B must not be equal to 2 or 4
For the relation not to be a function, B must either be 2 or 4
For example, if B = 2, the diagram for the relation is shown below:
The above is just a relation and not a function because when B = 2, an element of the set X is matched to more than one element in Y (1 and 3)