# The profit function for a new product is given by y= -4x^2 + 28x - 40, where x is the number sold in thousands. How many to break even?

### 2 Answers

- PuzzlingLv 72 months agoFavourite answer
The break even point is where the profit is 0.

Set it to zero and solve for x:

-4x² + 28x - 40 = 0

Let's simplify that by dividing everything by -4:

x² - 7x + 10 = 0

Factor that:(x - 2)(x - 5) = 0

So there are two potential solutions:

x = 2 or x = 5

Anything before 2 (thousand) units, they are losing money.

They break even when they sell 2 (thousand) units.

After that, the profit is positive.

When they sell 5 (thousand) units, they again are back to a profit of 0.

Anything above 5 (thousand) units, they are losing money once more.

Answer:

2 (thousand) or 5 (thousand) to break even.

- 2 months ago
y = 0

0 = -4x^2 + 28x - 40

0 = x^2 - 7x + 10

x = (7 +/- sqrt(49 - 40)) / 2

x = (7 +/- sqrt(9)) / 2

x = (7 +/- 3) / 2

x = 4/2 , 10/2

x = 2 , 5

After 2000 sold, they break even. Their profit peaks at 3500 sold and they start to lose money after 5000 sold.