John is building a rectangular puppy kennel up against his house using 31 feet of fencing. The side against the house does not need a fence and the side parallel to his house needs to be 15 feet long. Write an equation that models the situation and solve for the length of one of the shorter sides that extend out from the house.

Each of the shorter sides extended out from the house is 8 feet long.

Explanation:

So John, needs to make a 3 sided fence. He has 31 feet of fencing to do this with and the single side parallel to the house is 15 feet.

We can write the equation for this problem as:

31=2s+15

Where 31 is the total amount of fencing John has to use, 15 is the one side where the length is given, s is the length of each of the other two sides and because there are two sides we multiply s by 2

Solving this equation gives:

31-15=2s+15-15

16=2s+0

16=2s

162 = 2s 2

8=s