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 y=-4
Because it's like you do if backwards
Answer:

Step-by-step explanation:

Set up equation
Step 1: Simplify

Step 2:Multiply by conjugate

Step 3:Simplify

We can reduce this and we must make the imaginary number and real number serpate equations.

Reduce each by 2

Answer:
46 in²
Step-by-step explanation:
Given:
<span>mantle layer of earth begins about 70 kilometers underneath the surface
</span><span>outer core begins about 2970 kilometers underneath the surface
Since we need to find the position of each layer </span><span>relative to the surface, the surface will serve as the point of origin or 0. Below the surface infers a negative value. So, Mantle layer is -70 km from the surface while outer core is -2970 km under the surface.
Comparing -70 and -2970, -70 has a greater value than -2970. The nearer the number is to the origin or 0, the higher its value.
Comparing the absolute greater value of -70 and -2970, -2970 has a greater absolute value. This is because absolute value is the positive value of the number. Absolute value of -70 is 70 while absolute value of -2970 is 2970. Thus, -2970 has a greater absolute value. </span>