SOLUTION: The demand function for a new comic book is p(x)=-5x+30 where p(x) represents the selling price, in thousands of dollars and x is the number kd comic books sold, in thousands. What

Algebra ->  Quadratic Equations and Parabolas -> SOLUTION: The demand function for a new comic book is p(x)=-5x+30 where p(x) represents the selling price, in thousands of dollars and x is the number kd comic books sold, in thousands. What      Log On


   

Question 1090563: The demand function for a new comic book is p(x)=-5x+30 where p(x) represents the selling price, in thousands of dollars and x is the number kd comic books sold, in thousands. What is the maximum revenue? Revenue =[p(x)](x)
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
R%28x%29=%2830-5x%29x
R%28x%29=-5x%5E2%2B30x
Complete the square,
R%28x%29=-5%28x%5E2-6x%29
R%28x%29=-5%28x%5E2-6x%2B9%29%2B5%289%29
R%28x%29=-5%28x-3%29%5E2%2B45
So the revenue function is in vertex formula.
The maximum of 45 occurs when x=3.