Answer:
answers below
Step-by-step explanation:
1. no
2. yes
3. no
4. yes
5. no
6. yes
7. no
8. no
9. no
10. no
11. no
12. yes
Answer:
90 engines must be made to minimize the unit cost.
Step-by-step explanation:
Vertex of a quadratic function:
Suppose we have a quadratic function in the following format:

It's vertex is the point 
In which


Where

If a>0, the minimum value of the function will happen for 
C(x)=x²-180x+20,482
This means that 
How many engines must be made to minimize the unit cost?
x value of the vertex. So

90 engines must be made to minimize the unit cost.
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