Using the Quadratic Formula, what is the solution to the quadratic equation x2 - 9x + 20 = 0?

Abus ride for a senior citizen cost $1.25. a monthly pass costs $35. write and inequality that represents the number of times a senior citizen must ride the bus for the monthly pass to be a better deal.

Determine whether the set of whole numbers is closed under addition. explain why the set is or is not closed. give an example.

Aclassroom is made up of 11 boys and 14 girls. the teacher has four main classroom responsibilities that she wants to hand out to four different students (one for each of the four students). if the teacher chooses 4 of the students at random, then what is the probability that the four students chosen to complete the responsibilities will be all boys?