Question 29851
d=360/p ............(1)

s=150p-510 ..........(2)

it is given that at the equilibrium point when supply and demand equal.
thanks for the help,,so we get 


360/p = 150p - 510 

on multiplying both sides by p we get 

360 = 150p^2 - 510p

or 0 = 150p^2 - 510p - 360 

on dividing both sides by 30,, we get...

0 = 5p^2 - 17p - 360

Here you must know how we make factors i.e. splitting of the middle term...if you might not know then please contact me again and I will explain to you)... and we get......

0 =  5p^2 - (20 - 3)p - 360....solving the brackets wolud give...

0 =  5p^2 - 20p + 3p - 360

taking common from first two i.e. 5p^2 - 20p and last two i.e. 3p - 360
variables...we get 


0 = 5p (p-4) + 3(p-4)..

or 0 = (5p + 3)(p - 4)..

You know that the product two numbers or variables becomes equal to zero if atleast one of them is zero....
 
therefore either  (5p + 3) = 0
or (p - 4)= 0
 
if (5p + 3) = 0  the profit  = -3/5
and since profit can't be in negative so this can't be values of profit
 
and if  (p - 4)= 0 the profit  = 4

 or profit = 4 hundreds of thousands of dollars
 
hope this will help you 

Please feel free to revert back for any further queries.