Bob wants to fence in a rectangular garden in his yard. He has 70 feet of fencing to work with and wants to use it all. If the garden is to be x feet wide, how do you express the area of the garden as a function of x?

1 Answer
Oct 26, 2016

a = 35x - x^2

Explanation:

Having 70ft of fencing with a width of x feet and knowing the perimeter of a rectangle is p = 2w + 2l we can state the length of the garden as:

70 = 2x + 2l and solving for l we know the length with be:

2l = 70 - 2x
or
l = 35 - x

And then knowing the formula for the area of a rectangle is a = w * l we can write the equation as:

a = x * (35 - x)

a = 35x - x^2