SOLUTION: Can someone help me break this down and solve? I don't know what I am doing wrong. Thanks a million! A company has determined that when x hundred dulcimers are​ built, the

Algebra ->  Quadratic Equations and Parabolas -> SOLUTION: Can someone help me break this down and solve? I don't know what I am doing wrong. Thanks a million! A company has determined that when x hundred dulcimers are​ built, the      Log On


   

Question 1128480: Can someone help me break this down and solve? I don't know what I am doing wrong. Thanks a million!
A company has determined that when x hundred dulcimers are​ built, the average cost per dulcimer can be estimated by ​C(x)=0.3x^2−0.9x+2.175​, where​ C(x) is in hundreds of dollars. What is the minimum average cost per dulcimer and how many dulcimers should be built to achieve that​ minimum?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
the form is +f%28x%29+=+a%2Ax%5E2+%2B+b%2Ax+%2B+c+
+x%5Bmin%5D+=+-b%2F%282a%29+
+a+=+.3+
+b+=+-.9+
+x%5Bmin%5D+=+-%28-9%29%2F%282%2A.3%29+
+x%5Bmin%5D+=+9%2F.6+
+x%5Bmin%5D+=+15+
----------------------
Plug this back into equation to get C( 15 )
You then have 1500 dulcimers and the cost
to build them as answer ( x100 dollars )