Can u guys help with 15, a b c please help quick 100 points

What are the soultion(s) to the quadratic equation 40- x^2=0

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.

The amount spent on food and drink by 20 customers is shown below what is the modal amount spent ?