19-11+(-17)+(-19)+11?

Last month, a 770 g box of cereal was sold at a grocery store for $3.10. however, this month, the cereal manufacturer launched the same cereal in a 640 g box, which is being sold at $2.50. what is the percent change in the unit price?

When you have 25 numbers, and jake picks 3 random numbers and puts them back, what is the chance bob has of picking those 3 numbers when he picks 6 random numbers (without putting them back)? explain.

Two florida panthers were weighed. one weighs 6x+21 pounds and the two together weigh 14x+11 pounds how much does he other panther weigh alone