问题标题：
【初二数学-1/4x²+1/3xy-1/9y²（x²+1/4)²-2x(x²+1/4)+x²急啊!（1）-1/4x²+1/3xy-1/9y²（2）（x²+1/4)²-2x(x²+1/4)+x²10点之前给我!.】
问题描述：
初二数学-1/4x²+1/3xy-1/9y²（x²+1/4)²-2x(x²+1/4)+x²急啊!
（1）-1/4x²+1/3xy-1/9y²
（2）（x²+1/4)²-2x(x²+1/4)+x²
10点之前给我!.
郭祖华回答：
（1）-x²/4+xy/3-y²/9
=-(x²/4-xy/3+y²/9)
=-[(x/2)²-2*(x/2)*(y/3)+(y/3)²]
=-(x/2-y/3)²
(2)(x²+1/4)²-2x(x²+1/4)+x²
=(x²+1/4)²-2*(x²+1/4)*x+x²
=[(x²+1/4)-x]²
=[x²-2*x*(1/2)+(1/2)²]²
=[(x-1/2)²]²
=(x-1/2)^4
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