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用因式分解算 (交叉相乘)

来源:学生作业帮 编辑:作业帮 分类:数学作业 时间:2024/11/06 09:44:22
用因式分解算 (交叉相乘)
(1)
a6-7a3b3-8b6
=(a3+b3)(a3-8b3)
=(a+b)(a2-ab+b2)(a-2b)(a2+2ab+4b2)
(2)
6a4-5a3-4a2
=a2(6a2-5a-4)
=a2(3a-4)(2a+1)
(3)
4a6-37a4b2+9a2b4
=a2(4a4-37a2b2+9b4)
=a2(4a2-b2)(a2-9b2)
=a2(2a+b)(2a-b)(a+3b)(a-3b)
(4)
(x2-3)2-4x2
=(x2-3+2x)(x2-3-2x)
=(x-1)(x+3)(x+1)(x-3)
(5)
x2(x-2)2-9
=[x(x-2)-3][x(x-2)+3]
=(x2-2x-3)(x2-2x+3)
=(x-3)(x+1)(x-1)(x+3)
(6)
(3x2+2x+1)2-(2x2+3x+3)2
=(3x2+2x+1+2x2+3x+3)(3x2+2x+1-2x2-3x-3)
=(5x2+5x+4)(x2-x-2)
=(x+1)(x-2)(5x2+5x+4)
(7)
(x2+x)2-17(x2+x)+60
=(x2+x-5)(x2+x-12)
=(x-3)(x+4)(x2+x-5)
(8)
(x2+2x)2-7(x2+2x)-8
=(x2+2x-8)(x2+2x+1)
=(x+1)2(x+4)(x-2)