问题标题：
初二数学乘法公式化简题
问题描述：
初二数学乘法公式化简题
鲍春健回答：
有的看不清!猜的不对你再追问!
（1）（2x+y)?-(2x-y)?
=(2x+y+2x-y)(2x+y-2x+y)
=4x×2y
=8xy
(2)(a+b)(a-b)+(a+b)?-a(2a+b)
=a?-b?+a?+2ab+b?-2a?-ab
=ab
(3)(a+b-c)(a-b+c)-(a-b-c)(a+b+c)
=[a+(b-c)][a-(b-c)]-[a-(b+c)][a+(b+c)]
=[a?-(b-c)?]-[a?-(b+c)?]
=(b+c)?-(b-c)?
=4bc
(4)(a-2b+3c)(a+2b-3c)
=[a-(2b-3c)][a+(2b-3c)]
=a?-(2b-3c)?
=a?-4b?+12bc-9c?
(5)(3x+1)?(3x-1)?
=(9x?-1)?
=81x^4-18x?+1
(6)(x+1)(x?+1)(x^4+1)(x-1)
=(x?-1)(x?+1)(X^4+1)
=(x^4+1)(x^4-1)
=x^8-1
(7)(x-2y+z)(-x+2y+z)
=[z+(x-2y)][z-(x-2y)]
=z?-(x-2y)?
=z?-x?+4xy-4y?
(8)[(a+2b)-c]?
=(a+2b)?+c?-2c(a+2b)
=a?+2ab+4b?+c?-2ac+4bc
(9)(2a+b+1)(2a-b+1)
=(2a+1)?-b?
=4a?+4a-b?+1
(10)x(x-1)-(x?-y)=-2
-x-x?+y=-2
y-x=-2
(x?+y?)/2-xy
=1/2(x?+y?-2xy)
=1/2(x-y)?
=1/2×4
=2
后几个好像没化简啊!到麻烦了!但是这样的计算过程没错的!
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