Are the functions that represent these three students sales of hot chocolate linear?

Enter the number of complex zeros for the polynomial function in the box. f(x) = x+ + 5x² +6

Last week , donnell practiced the piano 3 hours longer than marcus . together, marcus and donnell practiced the piano 11 hours . for how many hours did each young man practiced the piano

The floor of a building consists of 3000 tiles which are rhombus shaped and each of it's diagonals are 45 cm and 30 cm in length. find the total cost of polishing the floor, if the cost per m² is rs. 4.