F.2 Mathematics Question!!!!!

As follows:

圖片參考：http://i707.photobucket.com/albums/ww74/stevieg90/04-56.jpg


2010-06-06 14:32:17 補充：
http://i707.photobucket.com/albums/ww74/stevieg90/04-56.jpg

2010-06-06 17:59:09 補充：
Q2:
1:1000
=>8cm:1000*8cm
=>8cm: 8000cm
=>8cm: 80m

the actual area=pi*80^2=6400pi m^2

5(x+y)^2-20(x+y)(x-y)+20(x-y)^2

5((x+y)^2-4(x-y)(x+y)+4(x-y)^2)

Let a=(x+y),b=(x-y)

5(a^2-4ab+4b^2)

5(a-2b)^2

5(x+y-2(x-y))^2

5(x+y-2x+y)^2

5(2y-x)^2

or

5(x+y)^2-20(x+y)(x-y)+20(x-y)^2

5((x+y)^2-4(x-y)(x+y)+4(x-y)^2)

5(x+y-2(x-y))^2

5(x+y-2x+y)^2
5(2y-x)^2



2010-06-06 16:12:50 補充：
更正:
5(x+y-2x+2y)^2
5(3y-x)^2

2010-06-07 21:36:42 補充：
the actual area of this garden is x:
1/1000=8^2(pi)/x
1/64000(pi)=1/x
x =64000(pi)cm

the actual area of this garden is 6400(pi)m^2