How do I simplify this math problem

-9c+9c-12

One hose can fill and goldfish pond in 28 minutes, and two hoses came for the same pond in 20 minutes. Find how long it takes a second holes alone to fill the pond

What does 'n' equal? (3n-7) / 6 = (2n+5) / 3

What formula do you use to find the volume of a cylinder?

What do you add to 3 1/7 to make 7

Joe has a board that is 6 feet long. He needs to cut the board into 15 equal lengths pieces. How many feet long should each piece of the board be?

Find all the real square roots of 0.0036

Lisa and Judy are wrapping gifts for their children. Lisa is making the bows. She has 37 and 1/3 yards of ribbon. If each bow uses 4 and 2/3 yards of ribbon, how many bows can Lisa make?

2,250 watts to horsepower (Round answer to the nearest thousandth.

10^m*10^n for m=2 and n=4

Convert 5 feet to inches. There are 12 inches in 1 foot. A) 15 inches B) 20 inches C) 50 inches D) 60 inches