MATH HELP ASAP!! MARKING BRAINLISET

The manufacturer of a new product developed the following expression to predict the monthly profit, in thousands of dollars, from sales of the productwhen it is sold at a unit price of x dollars.-0.5x^2 + 22x - 224what is represented by the zero(s) of the expression? a. the profit when the unit price is equal to 0b. the unit price(s) when the profit is equal to 0c. the profit when the unit price is greatestd. the unit price(s) when profit is greatest

Ijust need to see how to do this. so you don’t have to answer all of them just a step by step explanation of one.

The random variable x represents the number of phone calls an author receives in a day, and it has a poisson distribution with a mean of 8.7 calls. what are the possible values of x