(x-4y)^2-16(x-y)^2=? 求救
回答 (3)
2011-09-30 3:36 am
✔ 最佳答案
(x-4y)^2-16(x-y)^2=(x-4y)^2-(4(x-y))^2
=((x-4y)+4(x-y))((x-4y)-4(x-y))
=(x-4y+4x-4y)(x-4y-4x+4y)
=(5x-8y)(-3x)
=-3x(5x-8y)
參考: me
2011-10-01 7:35 pm
設a=(x-4y) b=(x-y)
(x-4y)^2-16(x-y)^2
=a^2-16b^2
=(a-4b)(a+4b)
=[(x-4y)-4(x-y)][(x-4y)+4(x-y)]
=(x-4y-4x+4y)(x-4y+4x-y)
=-5x(5x-5y)
=5x(5y-5x)
=25x(y-x)
(x-4y)^2-16(x-y)^2
=a^2-16b^2
=(a-4b)(a+4b)
=[(x-4y)-4(x-y)][(x-4y)+4(x-y)]
=(x-4y-4x+4y)(x-4y+4x-y)
=-5x(5x-5y)
=5x(5y-5x)
=25x(y-x)
2011-09-30 2:52 am
x-4y)^2-16(x-y)^2 = 2.
收錄日期: 2021-04-13 18:16:43
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20110929000051KK01036