Why is it important to be able to describe what each part of an expression or equation represent

In the coordinate plan (-6,9) b (3,9) c (3,3) def is shown in the coordinate plan below

Write a corresponding real world problem to represent 2x - 125=400

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.