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初二几道数学分式(1)(m²-3m)/9-m²(2)(3a²-ab)/(9a²-

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初二几道数学分式
(1)(m²-3m)/9-m²
(2)(3a²-ab)/(9a²-6ab+b²),其中a=3/4,b=-2/3
(3)(a²-b²)/(a²+ab)
(4)(a²+ab)/(a²+2ab+b²)
拜托速度T T
初二几道数学分式(1)(m²-3m)/9-m²(2)(3a²-ab)/(9a²-
(1)(m²-3m)/9-m²=m(m-3)/(3+m)(3-m)=-m/(m+3)
(2)(3a²-ab)/(9a²-6ab+b²)=a(3a-b)/(3a-b)²=a/(3a-b)=9/35
(3)(a²-b²)/(a²+ab)=(a+b)(a-b)/a(a+b)=(a-b)/a
(4)(a²+ab)/(a²+2ab+b²)=a(a+b)/(a+b)²=a/(a+b)