19) 2=-2 - 2a , for a A.) a= z+2/2

B.) a= 2z+4

C.) a= -z - 2/2

D.) a = -z+2/2

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?

Charlie tosses five coins.what is the probability that all five coins will land tails up.

Using only the digits 5, 6, 7, 8, how many different three digit numbers can be formed if no digit is repeated in a number?