Given the Quadratic Function

Find the Maximum Value and Minimum Value.

I have to find the value of a first which is 2. The problem is these 6 conditions.

1. When a < (blank)
2. When (blank)<=a<=(blank)
3.When a=(blank) (Let me guess, 2 is the answer.)
4.When (blank)<a<=(blank)
5.When a>(blank)

So I need help filling the answers. (blank) is what I need to answer but I am kind of confused.

Type the correct answer in the box. use numerals instead of words. if necessary, use / for the fraction bar. a city water tank holds 20 gallons of water. a technician empties 25% of the tank. how many more gallons of water must be removed from thetank so that it has 5 of the water that it started with: the technician must removemore gallons of water for the tank to have 5 of the water that it started with.