PLEASE HELP ASAP!!: explain the answer to this as well, please :)

the difference between two numbers is 4. the sum of the smaller number and theee times the larger number is 36. what are the two numbers?

Samantha is growing a garden in her back yard. she spend $90 setting up the garden bed and buying the proper garden supplies. in addition, each seed she plants cost $0.25. a. write the function f(x) that represents samantha's total cost on her garden. b. explain what x represents. c. explain what f(x) represents. d. if samantha plants 55 seeds, how much did she spend in total?