I need to find the function rule of the table​

Amovie streaming service charges it’s customers $15 a month. martina has $98 saved up. will she have any money left over if she pays for the maximum amount of months she can afford? explain.

If private savings 'v' = 0.75s and total savings 's' equals $4.20 billion, solve for public and private savings.

Pls never taught i’m really confused and i rlly need