Answer:
The answer is option C.
0 <= x <= 18
Step-by-step explanation:
To find the domain of the relationship in respect to x, we need to find the value of x.
Since;
youth tickets = $5 and
Adult tickets = $9.
Purchased x youth tickets and y adult tickets cost $90
Purchased x youth tickets and y adult tickets = 5x + 9y = 90
5x = 90 - 9y
to find x we divide both side by 5
x = (90-9y)/5
x = 90/5 - 9y/5
x = 18 - 9y/5
Note that in this equation x and y can only be positive value because that are representing number of legible item (ticket)
Therefore:
X can only fall between 0 and 18.
0 <= x <= 18