how many DVD/Blu-ray players were produced?

Question

A certain electronics manufacturer found that the marginal cost  to produce x DVD/Blu- ray players can be found using the equation . If the marginal cost were $276, how many DVD/Blu-ray players were produced?

Answer 1

276= .04x^2-8x+600

x^2-200x+25(324)=0

, solve by factoring, complete the square, quadratic formula or graphing

x^2 +200x + 10,000 = 8100 +10000

(x+10)^2 = 18,100

x = -10 + 10sqr18.1= about 32.5

ignore the negative square root