What 2 numbers multiply to 25 and add to 5

The total ticket sales for a high school basketball game were $2,260. the ticket price for students were $2.25 less than the adult ticket price. the number of adult tickets sold was 230, and the number of student tickets sold was 180. what was the price of an adult ticket?

Let f(x) = 5/x and g(x)=2x2+5x. what two numbers are not in the domain of f o g

Which one is the correct answer, and why?