What is the length of the line ? Distance between two points

1. what is the formula for finding the vertical distance between two points on a coordinate plane?

For which of the following counts would a binomial probability model not be reasonable? a)the number of people in a classroom born in januaryb) the number of people in a classroom with red hair c) the number of people admitted to a hospital in a day with a particular disease d) the number of heart beats in a one-minute perio.

Which equation represents a line that is parallel to the line whose equation is 3x-2y=7( show all work)