You can
put this solution on YOUR website!This graph is actually a parabola opening upward. The minimun cost will occur at the vertex, which is at

, where a is the coefficient of

and b is the coefficient of x. In this case, a=0.055 and b= -120.
Minimum cost =

=

=

= 1090.9 or 1091 units.
Things usually come out better than that, but then life doesn't always come out even, does it?
R^2 at SCC