數學唔識呀~!!(急用~!!)

2007-12-18 4:28 am
192x既3次方y+81yz既3次方
唔該哂各位幫幫忙~!!
更新1:

to STEVIE-G : 我想問下你中間係唔係少咗幾步呀?? 如果係可唔可以計埋俾我睇呀?? thz哂~!!

回答 (4)

2007-12-18 4:34 am
✔ 最佳答案
192x^3y+81yz^3
=3y(64x^3+27z^3)
=3y[(4x)^3+(3z)^3]
=3y(4x+3z)(16x^2-12xz+9z^2)

2007-12-17 21:22:44 補充:
(a^3 b^3)=(a b)(a^2-ab b^2)所以,[(4x)^3 (3z)^3]=(4x 3z)[(4x)^2-(4x)(3z) (3z)^2]=(4x 3z)(16x^2-12xz 9x^2)
2007-12-18 4:39 am
192x^3y+81yz^3 <<一定岩

=81y(2x^3+z^3) 一定俾你老師講好!!
參考: 老師
2007-12-18 4:34 am
81y(2 x3次方+z3次方)
2007-12-18 4:33 am
192x^3y+81yz^3
=81y(2x^3+z^3)
參考: me


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