word problem: finding quantity that minimizes cost

[Guest]

Minimizing cost:
A company uses the formula C(x)=0.02x^2 - 3.4x + 150 to model the unit cost in dollars for producing x stabalizer bars. For what number of bars is the unit cost at its minimum? What is the unit cost at the level of production?

Am I looking at setting up and completing through the use of the quadratic formula??
Thanks-
Caron

 

[tkhunny]

I think you're looking to recognize that C(x) is quadratic, therefore it's graph is a parabola and you should know some things about parabolas. One thing you should know is how to find the vertex.

 

[stapel]

Am I looking at setting up and completing through the use of the quadratic formula?

The Quadratic Formula finds the zeroes. You've been asked for the minimum, which is not the same thing.

Find the vertex, either by completing the square or by using the formula.

Eliz.