Answer:
D = {1, 4, 6, 8, 9}
Explanation:
A relationship maps elements from a set (the domain, the set of the inputs) into elements from another set (the range, set of the outputs).
Such that the usual notation is: (x, y)
this says that the relationship maps the element x into the element y.
In this case, we have the relation:
" { (9,1), (4,5), (6,2), (8,6), (1,2)}"
The inputs are the first value for each pair, then the set of the inputs (also called the domain) is:
D = {9, 4, 6, 8, 1}
And we can rewrite this in order to get:
D = {1, 4, 6, 8, 9}