let x = width

then length = (2x – 5)

p = 2x + 2(2x – 5) = 230

2x + 4x – 10 = 230

6x = 240

x = 40 = width

2(40) – 5 = 75 = length

proof

p = 2(75) + 2(40) = 150 + 80 = 230

Next, you know that the length is equal to 2 times W minus 5. In an eqution this is written as 2W -5 = L. Now all you have to do is substitute the amount 2W -5 into your first equation wherever you see an L.

2L + 2W = 230 now becomes 2(2W-5) + 2W = 230. Multilply this out and you get 4W -10 + 2W = 230. Add 10 to each side and you get 4W + 2W = 240 Add the 4W and 2W and now you have 6W = 240. Divide both sides by 6 and now you know that W = 40.

Go back you your first equations and substitute 40 for the W. 2L + 2(40) = 230. Multiply and now you have 2L + 80 = 230. Subtract 80 from each side and you get 2L = 150. Divide both sides by 2 and Voila! L = 75.

Width is 40

40+40+75+75=230

Figured that out in my head in less than 30 seconds– woohooo!

and width be W

and perimeter be P

L=2W-5

and P=2(L+W)=230

now substitute

2(2W-5+W)=230

2(3W-5)=230

3W-5=115

3W=120

W=40ft

but L=2W-5

then L=2(40)-5

L=80-5

L= 75ft

there u go, i think this is how its done.