# Thread: Application of revenue and cost function.

1. ## Application of revenue and cost function.

well first it would help if I knew how to type the math equation so if you can answer that it will help me in the future.. Here is the question.

daily revenue: R(x)=x^2-18
Daily Cost: C(x)=75+4x

How many items must be made and sold daily in order to break even.

I'm not sure what to do with this problem so any help to steer me in the correct direction is appreciated.

2. the break even point is when revenue = cost

$x^2 - 18 = 75 + 4x$

you'll need to use the quadratic formula to solve for x

3. x=25!!!

thanks

4. Originally Posted by jdv214
x=25!!!

thanks
how did you get x = 25?

5. I posted the original problem wrong. by forgetting the 'x' after 18. So...

x^2-18x-(75+4x)=0
x^2-22X-75=0
(X-25)(X+3)=0
x=25

When i plug that number back into the equation I get
R(x)=175
C(x)=175

It must be the correct answer.

6. Originally Posted by jdv214
I posted the original problem wrong by forgetting the 'x' after 18.
that would explain it.