What is the translate verbal expression to the cost c decreased by ten dollars

7x+8y=-18, 4x-9y=-3 solve the system of equations

Why did the ice arena get so hot after the big game (this is math related google it to find the paper

Mrs. morton has a special reward system for her class. when all her students behave well, she rewards them by putting 3 marbles into a marble jar. when the jar has 100 or more marbles, the students have a party. right now, the the jar has 24 marbles. how could mrs. morton reward the class in order for the students to have a party?