SOLUTION: A rectangular room containing 154 square feet is 3 feet longer than it is wide. How long of a piece of crown molding is needed to trim the perimeter of the ceiling?

You can easily solve it MENTALLY by noticing that  154 = 11*14  is the decomposition of the number 154 into the product 
of two numbers, whose difference is  3 = 14 - 11.


Alternatively, you can solve a quadratic equation


    x*(x+3) = 154,


where x is the unknown width.


Answer.  The dimensions are  11 ft by 14 ft  and the perimeter is  11+14+11+14 = 50 ft.