I pay a babysitter $8 per hour.
[tex]p=8t[/tex]
where p = pay ($) and t = time (hr)
Pick some values for t and substitute them into the formula to get the corresponding pay.
(0, 0) <--- no hours, no pay
(1, 8) <--- one hour, pay $8
(2, 16) <--- two hours, pay $16
etc.
[tex]\{(0,0), (1,8), (2,16), (3, 24), (4, 32), (5, 40)\}[/tex]