Question 980540:  A health club currently charges its 2,000 clients monthly membership dues of $44. The board of directors decides to increase the monthly membership dues. Market research shows that each $1 increase in dues will result in the loss of 7 clients. How much should the club charge each month to optimize the revenue from monthly dues? Round to the nearest cent. 
 Answer by josgarithmetic(39630)      (Show Source): 
You can  put this solution on YOUR website! PRICE___________CLIENTS_______________REVENUE 
44_________________2000 
44+1_____________2000-7 
44+2____________2000-2*7 
44+3____________2000-3*7 
. 
. 
44+x___________2000-7x_____________(44+x)(2000-7x)
 
 
Revenue is y=(44+x)(2000-7x) which represents a parabola, convex upward.  Being found in factored form, the zeros are easy to find; and the vertex, a maximum, occurs in the exact middle of the roots (zeros). 
  | 
 
  
 
 |   
 
 |