How can i tell if f(x)=400 in f(x)=4x-9 or if t(n)=400 in t(n)=4n-9?

Geometry: determine whether segment mn is parallel to segment kl. justify your answer. jm 6 mk 3 jn 8 nl 4

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?

The radius of the earth is two times the radius of the moon. what fraction of the volume of the earth is the volume of the moon?