A rectangle field with area of 1,500,000 needs to be fenced. 2W+2L=5,000. solve for L and W

so you would have

WL = 1500000
and W+L = 2500
or L = 2500-W

back into the 1st...
W(2500-W) = 1500000
-w^2 + 2500W - 1500000 = 0
w^2 - 2500W + 1500000=0
(W-1500)(W - 1000) = 0
W = 1500 or W = 1000

If W = 1500, then L = 1000
I W = 1000 , then L = 1500