The square of a number minus twice the number is 48. What is the number? (An explanation would be appreciated)

When i add money am i supposed to make it like this 7+12 or 7.00+12.00 because i got 19 dollars for my answer

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)

Who can me with this algebra for your guys.