Answer:
Width = 15 inches Length = 20 inches
Step-by-step explanation:
The area of a rectangle is calculated using the following formula.
(1)
Where L is the length and x is the width of the rectangle
In this case we know that the length of the rectangle is 5 inches greater than its width. This means that:
(2)
Also The area of a rectangle can be represented by the equation 
so to find the width x we solve the equation
(3)
For an equation of the form
the quadratic formula is:

In this case note that:

Then:




→ 
→ 
We take the positive solution 
Now we use equation (2) to find L