What is the type of this polynomial 9x^4y^9

The last time i bought this product , it cost $20.00 but it looks like it cost 29. 60 today? what is the increase

Which of the following would be a good name for the function that takes the weight of a box and returns the energy needed to lift it?

Atorch and a battery cost 2.50 altogether. the torch costs 1.50 more than the battery. what fraction of the total price is the torch? give your answer in its simplest form.