求解x的平方十y的平方。能否用平方差公式来分解因式?为什么?
\u5229\u7528\u5e73\u65b9\u5dee\u516c\u5f0f\u5206\u89e3\u56e0\u5f0f \uff08\u4e00\uff09x\u7684\u4e8c\u6b21\u65b9\uff08y-1\uff09+\uff081-y\uff09\u5229\u7528\u5e73\u65b9\u5dee\u516c\u5f0f\u5206\u89e3\u56e0\u5f0f
\uff08\u4e00\uff09x\u7684\u4e8c\u6b21\u65b9\uff08y-1\uff09+\uff081-y\uff09
=x²(y-1)-(y-1)
=(y-1)(x²-1)
=(y-1)(x-1)(x+1)
\uff08\u4e8c\uff09
\uff08a+2b\uff09\u7684\u5e73\u65b9-\uff08a-3b\uff09\u7684\u5e73\u65b9
=(a+2b-a+3b)(a+2b+a-3b)
=5b*(2-b)
\uff08\u4e09\uff09 \u5229\u7528\u56e0\u5f0f\u5206\u89e3\u8ba1\u7b97
1003*997
=(1000+3)(1000-3)
=1000000-9
=999991
2008\u7684\u5e73\u65b9-2007\u7684\u5e73\u65b9
=(2008-2007)(2008+2007)
=1*4015
=4015
\uff0856*\u4e8c\u5206\u4e4b\u4e09\uff09\u7684\u5e73\u65b9-\uff0843*\u4e00\u5206\u4e4b\u4e09\uff09\u7684\u5e73\u65b9
=(56*2/3-43*1/3)(56*2/3+43*1/3)
=69/3*155/3
=23*155/3
=3565/3
2.89*52\u7684\u5e73\u65b9-2.89*48\u7684\u5e73\u65b9
=2.89\u00d7(52²-48²)
=2.89\u00d7(52-48)(52+48)
=2.89\u00d7100\u00d74
=289\u00d74
=1156
\uff08\u56db)\u7ed9\u51fa\u4e09\u4e2a\u591a\u9879,X=2a\u7684\u5e73\u65b9+3ab+b\u7684\u5e73\u65b9\uff0cy=3a\u7684\u5e73\u65b9+3ab\uff0cZ=a\u7684\u5e73\u65b9+ab\uff0c\u8bf7\u4f60\u4efb\u9009\u8fde\u4e2a\u8fdb\u884c\u52a0\u6216\u8005\u51cf\u8fd0\u7b97\uff0c\u518d\u5c06\u7ed3\u679c\u5206\u89e3\u56e0\u5f0f\u3002
x+y+z
=2a²+3ab+b²+3a²+3ab+a²+ab
=6a²+7ab+b²
=(6a+b)(a+b)
\u89e3\uff1a(x+y)^2-(x-y)^2
={(x+y)+(x-y)}{(x+y)-(x-y)}
=2x * 2y
=4xy
不能，因为平方差公式是减，不是加，
不能，分解不了
在复数范围内可用
x^2+y^2=x^2-(yi)^2=(x+yi)(x-yi)
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绛旓細鍏堝畾涔夌Н鍒嗙鍙凤細S(a,b)f(x)dx 鍗充负f(x)鍦▁=(a,b)鍖洪棿鐨勫畾绉垎,涓嬮檺涓篴,涓婇檺涓篵 x^2 + y^2 = 4 閫氳繃 x^2 + y^2 = 4 鍜 y = 1 瑙ｇ畻鍑篺(x)鐨勫尯闂,a = -鈭3,b = 鈭3 涓嬮潰鍋氬畾绉垎锛氫粠x鍙栧煎尯闂村垽鏂嚭y澶т簬0,鎵浠ワ細y = 鈭(4 - x^2) = 2鈭歔1 - (x/2)^...
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