Directly proportional or positively correlated
A. 6(k + s)
It's the distributive property.
2nd degree and in form
ax^2+bx+c
it is a prabola
the minimum cost is the vertex (every parabola has only one, min or max)
minimum cost is the vertex
vertex=-b/(2a)
a=0.4
b=-208
vertex=-(-208)/(2*0.4)
vertex=208/0.8
vertex=260 (means 260 dresses)
that is x value
subsitute for y value
C(x)=0.4(260)^2-208(260)+37365
C(x)=10325
minimum cost is $10,325
