f.4 Polynomials

2010-01-27 2:01 am
(x^2+x-2/x^3+x^2) / (x^2+2x-3/x^2+3x)

回答 (3)

2010-01-27 5:32 am
✔ 最佳答案
螞蟻雄兵錯了:

[ (x^2+x-2)/(x^3+x^2) ] / [ (x^2+2x-3) / (x^2+3x) ]

= [ (x^2+x-2) / (x^3+x^2) ] * [ (x^2+3x) / (x^2+2x-3) ]

= (x^2+x-2)(x^2+3x) / [ (x^3+x^2)(x^2+2x-3) ]

= (x-1)(x+2) (x)(x+3) / [ (x^2)(x+1) (x-1)(x+3) ]

= (x+2) / [x(x+1)]

2010-01-26 21:32:44 補充:
[ (x^2+x-2)/(x^3+x^2) ] / [ (x^2+2x-3) / (x^2+3x) ]

= [ (x^2+x-2) / (x^3+x^2) ] * [ (x^2+3x) / (x^2+2x-3) ]

= (x^2+x-2)(x^2+3x) / [ (x^3+x^2)(x^2+2x-3) ]

= (x-1)(x+2) (x)(x+3) / [ (x^2)(x+1) (x-1)(x+3) ]

= (x+2) / [x(x+1)]

x 不等如 0,否則分母 x^3+x^2 及 x^2+3x 是 0 ,分母不可為0

ThankYou!!



2010-01-26 21:40:56 補充:
(x^3+x^2)及(x^2+3x)不可為0

x^3 + x^2 = (x^2)(x + 1) =/= 0

x =/= 0 and x =/= - 1

x^2 + 3x = x(x+3) =/= 0

x =/= 0 and x =/= - 3

x 不等如 0 , - 1 , - 3
2010-01-27 4:26 am
系. tonyleung052 岩左.
thx 但你不如回答啦,
你淨系比意見 我加吾到你分,同埋簡吾到你做最佳回答的..
2010-01-27 2:56 am




[(x^2+x-2)/(x^3+x^2)] /[ (x^2+2x-3)/(x^2+3x)]

Sol

不考慮分母=0

[(x^2+x-2)/(x^3+x^2)]
/[ (x^2+2x-3)/(x^2+3x)]

=[(x^2+x-2)*(x^2+3x)]/[(x^3+x^2)*(x^2+2x-3)]

=[(x+2)(x-1)x^2(x+1)]/[x^2(x+1)(x+3)(x-1)]

=(x+2)/(x+3)








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