Mitosis and meiosis escape room level 5

please help​

What is the range? can’t seem to find it out

1- what do you think the product of a nonzero rational number and an irrational number is? is it rational or irrational? make use of variables, the closure property of integers, and possibly a proof by contradiction to prove your hypothesis.2- why do we have to specify that the rational number must be nonzero when we determine what the product of a nonzero rational number and an irrational number is? if the rational number were 0, would it give us the same result we found in the first question?

What is the axis of symmetry of the function f(x)=-(x+ 9)(x-21)