Math Question????? Help Please?? 10 Points Best Answer?

Hiring a bulldozer and operator costs $360 plus a variable cost that is a funtion of the number of hours worked. The cost is $26 - 4.05x, where x is the number of hours. The total cost of hiring a bulldozer and operator is given by the function C(x) = $360 + 26x - 4.05x^2. For what value of x will this function be maximized?





[a] x = 6.5


[b] x = 3


[c] x = 5.5


[d] x = 2





Please show me how to do this.

Math Question????? Help Please?? 10 Points Best Answer?
For maximum profit you should use this formula :


-b/2a





-26/2(-4.05)


26/8.1





Is about 3.2.





Seems like b works!
Reply:$360 + 26x - 4.05x^2





take the derivative and set equal to zero


26 - 8.1x = 0


- 8.1x = -26


x = 26/8.1 = 3.2





b is the answer.