If P=5x^4+4x-3 and Q=5x^4+3x^3-4x+3, what is p - q

What are “like terms”? why can we only add like terms?

Which equation can be used to measure the density of water in a spherical water tank? let w represent the number of water particles within the region.

Tony is charged $ 50 and additional $0.15 per miles for renting a car. a) represent the cost of renting a car with an equation,and the determine the cost if he drove it70 miles.b) what would be the cost of a car rental if the car was driven 250 miles? show work