9514 1404 393
Answer:
 20 ≤ x ≤ 30
Step-by-step explanation:
The profit function is ...
 profit = revenue - cost
 = (-x^2 +80x) -(30x +600)
 = -x^2 +50x -600
 = -(x -20)(x -30)
The profit function will be positive where the signs of the factors are different: for x-values between 20 and 30. The profit function will be zero for x=20 and x=30.
The company will break even or make a profit for values of x that satisfy ...
 20 ≤ x ≤ 30
