Question

Suppose you have 54 feet of fencing to enclose a rectangular dog pen. The function a=27x-x^2, where x=width, gives you the area of the dog pen in square feet. What width gives you the maximum area? Round to the nearest tenth as necessary.

Answer 1

any idea ?

Answer 2

a couple ways to approach this
1. graph and find the vertex using graphing software
2. find the vertex of the parabola with x = -b/(2a)
3. might be ahead of what you're learning but you can take the derivative, set it equal to 0, and solve for x