The relation R is defined by the ordered pairs listed below. R = {(- 9,0), ( – 4, – 1), ( – 1, – 20), (6, 10), (9, 19)}
The domain of Ris
The range of Ris
Is R a function?
Yes, the relation is a function
No, the relation is not a function

I'm confused on this could anyone me and show me what i need to do to solve it.

Hassan bought a package of tofu. the temperature of the tofu was 14° celsius when hassan put the package into the freezer. he left the tofu in the freezer until it reached –19° celsius. which expressions explain how to find the change in temperature, in degrees celsius, of the package of tofu? select three that apply.

Derek purchased a new gym membership. it costs him seven dollars a month plus two dollars for every time that he visits the gym. he wants to spend less than 25 dollars a month to visit the gym. write an inequality that models the situation using the variable v for the number of visits per month. also find the maximum number of visits he can make to the gym and still keep his cost below 25 dollars a month.