高初中因式分解

Question

如题所述

Answer 1

1.(x－y)²＋3(x²－y²)－4(x＋y)²
=(x－y)²＋3(x＋y)(x－y)－4(x＋y)²
=[(x－y)＋4(x＋y)][(x－y)－(x＋y)]
=﹣2y(5x＋3y)

2.x²－xy－2y²－x－y
=(x－2y)(x＋y)－(x＋y)
=(x＋y)(x－2y－1)
3.14x²－67xy＋18y²
=(2x－9y)(7x－2y)
4.x²－y²＋5x＋3y＋4
=(x＋y)(x－y)＋5x＋3y＋4
=(x＋y＋1)(x－y＋4)

5.2x²－8xy＋8y²－11x＋22y＋15
=2(x²－4xy＋4y²)－11(x－2y)＋15
=2(x－2y)²－11(x－2y)＋15
=(x－2y－3)[2(x－2y)－5]
=(x－2y－3)(2x－4y－5)

不懂的还可以问！满意请及时采纳！ O(∩_∩)O追问

求解释

追答

1.(x－y)²＋3(x²－y²)－4(x＋y)²
=(x－y)²＋3(x＋y)(x－y)－4(x＋y)²[把 (x－y)和(x＋y)分别看成一个整体再十字相乘]
=[(x－y)＋4(x＋y)][(x－y)－(x＋y)]
=﹣2y(5x＋3y)

2.x²－xy－2y²－x－y
=(x－2y)(x＋y)－(x＋y)(先十字相乘,再提公因式)
=(x＋y)(x－2y－1)
3.14x²－67xy＋18y²
=(2x－9y)(7x－2y)(十字相乘)
4.x²－y²＋5x＋3y＋4
=(x＋y)(x－y)＋5x＋3y＋4(把x＋y和x－y分别看成一个整体再十字相乘)
=(x＋y＋1)(x－y＋4)

5.2x²－8xy＋8y²－11x＋22y＋15
=2(x²－4xy＋4y²)－11(x－2y)＋15
=2(x－2y)²－11(x－2y)＋15(把x－2y看成一个整体再十字相乘)
=(x－2y－3)[2(x－2y)－5]
=(x－2y－3)(2x－4y－5)

结合我的提示,稍微想想,再看看书应该会懂的!
祝你学习进步!

Answer 2

1．(x－y)²＋3(x²－y²)－4(x＋y)²=(x－y)²＋3(x＋y)(x－y)－4(x＋y)²=[(x－y)＋4(x＋y)][(x－y)－(x＋y)]=﹣2y(5x＋3y)2．x²－xy－2y²－x－y=(x－2y)(x＋y)－(x＋y)=(x＋y)(x－2y－1)3．14x²－67xy＋18y²=(2x－9y)(7x－2y)4.x²－y²＋5x＋3y＋4=(x＋y)(x－y)＋5x＋3y＋4=(x＋y＋1)(x－y＋4)5．2x²－8xy＋8y²－11x＋22y＋15=2(x²－4xy＋4y²)－11(x－2y)＋15=2(x－2y)²－11(x－2y)＋15=(x－2y－3)[2(x－2y)－5]=(x－2y－3)(2x－4y－5)可以直接加qq279674580追问

求解释

追答

什么意思我不懂