The area of a rectangular wall of a barn is 133 square feet. it's length is 12 feet longer than the width. find the length and width of the wall of the barn

I'll give you a few hints. Area of a rectangle is length times width. We know that length times width is 135 sq ft, so we can express it as: 

L * W = 135 

Now, L is 6 feet longer than width (L = 6 + W). Something tells me this is going to involve a quadratic formula then plugging in values into our original equation.