第1个回答 2015-08-11
(a+b+c)²-(a-b-c)²
=(a+b+c+a-b-c)(a+b+c-a+b+c)
=4a(b+c)
x³+3x²-4x-12
=x²(x+3)-4(x+3)
=(x+3)(x²-4)
=(x+3)(x+2)(x-2)
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第2个回答 2015-08-11
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第3个回答 2015-08-11
(a+b+c)²-(a-b-c)²
=(a+b)²+2(a+b)c+c²-(a-b)²+2(a-b)c-c²
=a²+2ab+b²+2ac+2bc-a²+2ab-b²+2ac-2bc
=4ab+4ac
第5个回答 2015-08-11
4a×(b+c),(x+3)×(x+2)×(x-2)