9. Emma is choosing new tile for the floor in his dining room, which is in the
shape of a square with side length x feet. The tile costs $3.50 per square foot.

a. Write the function f for the cost of the flooring.

b. Determine the cost of the flooring if she decides on a dining room with side
lengths of 10 ft.

c. Determine the cost of the flooring if she decides on a dining room with side
lengths of 15 ft.