Is this a function. ?

Aboat costs 19200 and decreases in value by 12% per year. how much will it cost in 5 years

Tod does not have any cookies. david gives jeff 8 cookies. then he splits half of the cookies he has left with tod. david let’s c represent the number of cookies that he starts with. he finds the number of cookies that tod has is 1/2 the difference of c and 8. write an expression to represent the number of cookies that tod has.

How do you write y-10=2 (x-8) in standard form