Simplify the equation 3x^2-2x^2

Two airplanes start at the same place and travel in opposite directions,one at 395 miles per hour and the other at 422 miles per hour. how many hours will it take for the planes to be 2451 miles apart?

The length of a rectangle plus its width is 24 cm. the area is 143 square cm. what are the length and width of the rectangle?

Susan is paying $0.30 per $100 on her $483,000 home in homeowners insurance annually. if her annual homeowners insurance premium is divided into twelve equal monthly installments to be included on each of her monthly mortgage payments of $2,128.00, what is her total monthly payment?