(x - 2) + (x + 6) what is the sum or difference

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.

Haley buys 9 pounds of apples for $3. how many pounds of apples can she buy for $1?

What is the best way to answer questions with a x expression in the question. for example 3x + 10x=?