math
posted by Jane on .
You are planting a rectangular garden. It is 5 ft longer than 3 times its width. The area of the garden is 250 ft^2. Find the dimensions of the garden.
I set it up like this: 3x +5 = 250 where x=8l.7. Is this correct so far, if so what do I do next? Thanks

L = 5 + 3 w
L w = 250 so L = 250/w
then
250/w = 3 w + 5
250 = 3 w^2 + 5 w
3 w^2 + 5 w  250 = 0
(3 w  25 ) (w + 10 ) = 0
w = 10
or
w = 25/3 use + 25/3
L = 250 *3/25 = 30