SOLUTION: a dog pen has an area of 60 square feet the width of the pendants two feet shorter than the left find the length of the pen?

Question 1071205: a dog pen has an area of 60 square feet the width of the pendants two feet shorter than the left find the length of the pen?
Answer by Dirichlet(3) (Show Source): You can put this solution on YOUR website!
Let:
w = the width of the pen
l = the length of the pen
The width is 2 feet shorter than the width, so this gives:

The area A of a rectangle is:

Substituting in w, we get:

The area A also equals 60. So, we get:

Distribute l:

Bring the 60 over and we get:

Using the quadratic formula,

Solved by pluggable solver: SOLVE quadratic equation (work shown, graph etc)

Quadratic equation (in our case ) has the following solutons:

For these solutions to exist, the discriminant should not be a negative number.

First, we need to compute the discriminant : .

Discriminant d=244 is greater than zero. That means that there are two solutions: .

Quadratic expression can be factored:

Again, the answer is: 8.81024967590665, -6.81024967590665. Here's your graph:

(Note: l is and ugly number!)
Only the positive answer makes sense, 8.8102...
To find w, subtract 2 from l.
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