If the profit function is Px x2 180x 5600 find breakeven

If the profit function is P(x) = -x^2 + 180x - 5600, find break-even points. x = 40, x = 140 x = 180, x = 5600 x = 90, x = 0 x = 90

Solution:

Here;

P(x) = -x^2 + 180x -5600

=> x = {-180±sqrt(180^2 -4*(-1)(-5600)) }/ 2*(-1)

=> x = {-180±100} / -2

=> x = 40 ,140

(A)