You can write two equations using the given information: .. L = W +8 .. L * W = 609 Using substitution, you get a quadratic. .. (W +8) * W = 609 .. W^2 +8W -609 = 0 Not surprisingly, you're looking for factors of 609 that differ by 8. .. 609 = 1*609 = 3*203 = 7*87 = 21*29 The last two are the factors of interest. .. (W +29)(W -21) = 0
The width of the rectangle is 21 feet, the length is 29 feet.
_____ Sometimes it is easier to work with the average dimension. Here, let that be x. Then you have .. (x +4)(x -4) = 609 .. x^2 -16 = 609 .. x^2 = 625 = 25^2 . . . . . . . one of your memorized math facts So, the dimensions are .. 25 +4 = 29 by 25 -4 = 21, that is, 29 ft by 21 ft.