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