Answer:
Manufacturers has to produce 63 DVD/Blu-Ray players to achieve a minimum cost of $644
Step-by-step explanation:
The cost equation is given as:

This is a quadratic equation in general form, which is:

Matching, we can say:
a = 0.04
b = -5
c = 800
The minimum occurs at 
and the minimum value would be to place that "x" value into the equation.
First, we find the minimum using values of a and b:

Plugging this into original, we get:

Rounding off to nearest whole number, we can say:
Manufacturers has to produce 63 DVD/Blu-Ray players to achieve a minimum cost of $644
Answer:
8
Step-by-step explanation:
They only won 25%
25%=1/4
32/4=8
They won 8 games
Well the square root of 72 is 8.485 and the square root of 45 is 6.708. hope this helps :)