9. You have a record of your age x (in years) and your height y (in inches) on each of your birthdays since you were born. Is this a function?

Step-by-step explanation:

The y's can be a duplicate and g(x) can still be a function. Since travelling back in time is not possible, all most all ages along the x axis will produce a function as long as x>0.

It doesn't have to be much over 0 to start counting it. As soon as birth occurs height can be measured and usually is.

12r - 8 - 12

you have to combine like terms. below i have bolded the like terms:

12r - 8 - 12

together it combines to:

12r - 20

hope this !

answer: i think it is c