(xy-1)(x-1)(y+1)-xy
幫我做因式分解,唔該哂!
唔該幫我factorize左佢
2008-06-08 5:59 am
回答 (2)
2008-06-08 6:21 am
✔ 最佳答案
(xy-1)(x-1)(y+1)-xy=(xy-1)(xy+x-y-1) -xy
=(xy-1)(xy-1+x-y) -xy
= (xy-1)^2 + (xy-1)( x-y) -xy
=(xy-1+x) (xy-1-y)
=(xy+x-1)(xy-y-1)
2008-06-08 6:26 am
(xy-1)(x-1)(y+1)-xy
= (xy-1)(xy+x-y-l)-xy
= (xy)^2 - xy + (x^2)y - x - xy^2 + y + l - xy
= (xy)^2 + (x^2)y - xy^2 - 2xy - x + y + l
= (xy)^2 + (x^2)y - xy^2 - xy - xy - x + y + l
= xy(xy + x - y - l) - (xy + x - y - l)
= (xy + x - y - l)(xy - l)
= (xy-1)(xy+x-y-l)-xy
= (xy)^2 - xy + (x^2)y - x - xy^2 + y + l - xy
= (xy)^2 + (x^2)y - xy^2 - 2xy - x + y + l
= (xy)^2 + (x^2)y - xy^2 - xy - xy - x + y + l
= xy(xy + x - y - l) - (xy + x - y - l)
= (xy + x - y - l)(xy - l)
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