math
posted by cris on .
A homeowner wants to plant a garden in his backyard. He decides to have 375 square feet garden and wants the garden to be 10 feet longer than it is wide. Find the dimensions of the garden.

L=W+10
area= LW=375
375=W(W+10)
w^2+10W375=0
completing the square
W^2+10w+25=400
(w+5)=20
w=15,L=25 
width  x ft
length  x+10 ft
solve
x(x+10) = 375
x^2 + 10x  375 = 0
(x+25)(x15) = 0
x = 15 or x = a negative
width: 15 ft
length : 25 ft
check: 15x25 = 375