Pls help me this and explain for me pls

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?

Valentina is subtracting from . she finds the lcd to be 15y2. what is valentina's next step?

Hurry which expression is equivalent to 3√x^5y?