8.25 or 9 .....................................................................................
The answer would be false.
Since the figure above is a square, that would mean all sides are equal size. If x=5, that would make segment AD bigger than segment BC.
Answer:
600
Step-by-step explanation:

x max = 
a = -5
b = 6
-6/2(-5) = 6/10 = 3/5 = .6
.6 thousand = 600
600 speakers should be sold.
Alternatively, you can check the vertex of the parabola formed.