Answer:
200
Step-by-step explanation:
Given that C(x) = 0.1[tex]x^{2}[/tex] - 40x +9569,
complete the square, then C(x) = 0.1* ( [tex]x^{2}[/tex] - 400x) +9569
= 0.1 * ([tex]x^{2}[/tex] - 400x + [tex](400/2)^{2}[/tex]) +9569 - [tex](400/2)^{2}[/tex]
= 0.1 * (x - 200)^2 - 30431
so the answer is 200 machines