Question 1058270
To produce 40 bikes: 
A) C(40) = 40^2-40*40+530 = 530
:
B)x^2-40x+530 = 130
x^2-40x+530-530 = 130-530
x^2+(-40)x = -400 Take one half the coefficient of x (-40/2 = -20) and square it, then add to both sides:
x^2+(-40)x+400 = 0 We have a perfect square. Factor it:
(x-20)^2 = 0 Take the sqr rt on both sides
x-20 = 0
x = 20
:
You do C, I'm tired of this problem.