There's again something too difficult for me, I hope you can help me
You have a garden whose area is 18 sq ft and perimeter's 18 ft. It's length is x and width is y.
The first question says to write equations about this, and I think I've gone so far: a=x*y. p=2y+2x. Right? OK. Now comes the extremly difficult part:
1)Prove that (x+y)^2-4xy=(x-y)^2?
With the expand-and-solve thing I ended up with this: x^2+y^2-4xy=x^2+y^2. Is that right? And how can it help me prove that (x+y)^2-4xy=(x-y)^2?
2)Using the results of question 1, calculate (x-y)^2 and find x-y.
3)Using the results of question 2, calculate x and y.