(x-y)的平方的完全平方公式 (x+y-50的平方用完全平方公式解
x-y \u7684\u5b8c\u5168\u5e73\u65b9\u516c\u5f0f\u7684\u7b97\u6cd5\uff1f\uff08x-y\uff09²
=x²-2xy+y²
(x+y-50)²
=(x+y)²-100(x+y)+2500
=x²+2xy+y²-100x-100y+2500
\u5f88\u9ad8\u5174\u4e3a\u60a8\u89e3\u7b54\uff0c\u795d\u4f60\u5b66\u4e60\u8fdb\u6b65\uff01\u3010the1900\u3011\u56e2\u961f\u4e3a\u60a8\u7b54\u9898\u3002
\u6709\u4e0d\u660e\u767d\u7684\u53ef\u4ee5\u8ffd\u95ee\uff01\u5982\u679c\u60a8\u8ba4\u53ef\u6211\u7684\u56de\u7b54\u3002
\u8bf7\u70b9\u51fb\u4e0b\u9762\u7684\u3010\u9009\u4e3a\u6ee1\u610f\u56de\u7b54\u3011\u6309\u94ae\uff0c\u8c22\u8c22\uff01
\u5982\u679c\u6709\u5176\u4ed6\u9700\u8981\u5e2e\u52a9\u7684\u9898\u76ee\uff0c\u60a8\u53ef\u4ee5\u6c42\u52a9\u6211\u3002\u8c22\u8c22\uff01
x²-2xy+y²
解：
(x-y)²
=(x-y)(x-y)
=x(x-y)-y(x-y)
=x²-xy-xy+y²
=x²-2xy+y²
x²-2xy+y²
绛旓細(x-y)²=(x-y)(x-y)=x(x-y)-y(x-y)=x²-xy-xy+y²=x²-2xy+y²
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绛旓細杩欐槸瀹屽叏骞虫柟鍏紡 (x-y)鐨勫钩鏂=x鐨勫钩鏂-2xy+y鐨勫钩鏂 (x+y)鐨勫钩鏂=x鐨勫钩鏂-2xy+y鐨勫钩鏂 鍙傝冭祫鏂欙細http://baike.baidu.com/view/26374.htm?fr=ala0_1_1
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