# Math Help - function price-demand

1. ## function price-demand

price-demand function is this:

= 200 - x/50

now the revenue equals (200 - x/50)x

now i have a problem with the multiplication of x.

of course, it is 200x, but then?

200x - (x/50 * x ??)

how can i get rid of the fraction?

2. Originally Posted by makaveli89
price-demand function is this:

= 200 - x/50

now the revenue equals (200 - x/50)x

now i have a problem with the multiplication of x.

of course, it is 200x, but then?

200x - (x/50 * x ??)

how can i get rid of the fraction?
It is $200x - \frac{x^2}{50}$

You could multiply everything by 50 if you wanted to clear the fraction. If we say that the price demand function is f(x):

$50f(x) = 10^4x - x^2 = x(10^4-x)$

3. cool thx. what will be f'(x)?

200- 2x/50 ??

4. Originally Posted by makaveli89
cool thx. what will be f'(x)?

200- 2x/50 ??
Yes but normally you'd cancel 2x/50 to x/25