初二的几道分式题通分：1.2ab分之3c,3ac^2分之b,4b^2c分之a2.2x+2分之x+2,x^2-x-2分之x,8-4x分之33.5b^2c分之4a,10^2b分之3c,-2ac^2分之5b4.a^2+2a+1分之a-1,a^2-1分之1化简：m^2-4n^2分之m^2-4mn-12n^2

Question

初二的几道分式题
通分：
1.2ab分之3c,3ac^2分之b,4b^2c分之a
2.2x+2分之x+2,x^2-x-2分之x,8-4x分之3
3.5b^2c分之4a,10^2b分之3c,-2ac^2分之5b
4.a^2+2a+1分之a-1,a^2-1分之1
化简：
m^2-4n^2分之m^2-4mn-12n^2

Answer 1

3c/2ab=18bc^3/12ab^2c^2
b/3ac^2=4b^3/12ab^2c^2
a/4b^2c=3a^2c/12ab^2c^2
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(x+2)/(2x+2)=2(x+2)^2(x-2)/4(x-2)(x+2)(x+1)
x/(x-2)(x+1)=4x(x+2)/4(x-2)(x+2)(x+1)
3/(8-4x)=-3(x+1)(x+2)/4(x-2)(x+2)(x+1)
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4a/5b^2c=8a^3c/10a^2c^2b^2
3c/10a^2b=3c^3b/10a^2b^2c^2
5b/-2ac^2=-25b^3a/10a^2b^2c^2
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(a-1)/(a^2+2a+1)=(a-1)/(a+1)^2=(a-1)^2/(a+1)^2(a-1)
1/(a^2-1)=1/(a+1)(a-1)=(a+1)/(a+1)^2(a-1)
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原式=(m^2-4mn-12n^2)/(m^2-4n^2)=(m-6n)(m+2n)/(m+2n)(m-2n)=(m-6n)/(m-2n)