Please guys i really need your help for this question

To solve the system of equations below, grace isolated the variable y in the first equation and then substituted into the second equation. what was the resulting equation? 3y=12x x^2/4+y^2/9=1

Fred and gene are hang gliding. fred is 700 feet above the ground and descending at 15 ft/s. gene is decending as shown in the table. interpret the rates of change and initial values of the linear functions in terms of the situations they model. show all work. freds equation is f(x)=-15x+700. ( genes is the table attached)

15. jiovanni is looking in to two different companies that offer study guides for math exams. test prep 101 charges a $5 flat fee and an additional $0.25 per problem. math charges a $2 flat fee and an additional $0.50 per problem. how many prablems would make the costs of the two companies be equal? varibles: equations/eniqualities{ {