A rectangular flower bed has a width of x feet and a perimeter of 156 feet. Find x such that the area of the rectangle is maximized.

Answer 1

156 = 2x + 2L

156 - 2x = 2L

78 - x = L

Area = Length * width

= (78-x)x

the extrema occurs at the average of the solutions to the quadratic function

x=39