jtk2005
春芽
共回答了21个问题采纳率:85.7% 举报
(1)当x_≠-1/2___时,分式2x+1分之2x-3有意义,当x___=3/2___时,分式2x+1分之2x-3的值为0
分母等于0时,分式没有意义
分式的值等于0,分子等于0,而分母不等于0
(2)3a²b分之9ab²+6abc=
=3ab(3b+2c)/3a²b
=(3b+2c)/a
(3)1-a分之a²-2a+1=1-a 这个式子对不对,如果不对,请写出正确答案
1-a分之a²-2a+1
=(a-1)²/(1-a)
=(1-a)²/(1-a)
=1-a 你写的是对的
(4)(x+y)²分之2xy与x²-y²分之x(通分
x²-y²=(x+y)(x-y)
∴两个分式的最简公分母是(x+y)²(x-y)
2xy/(x+y)²=2xy(x-y)/(x+y)²(x-y)
x/(x²-y²)=x/(x+y)(x-y)=x(x+y)/(x+y)²(x-y)
(5)a³-3a²+2a分之1,与a的4次方-a²分之2与a²+a-2分之-1(通分)
a³-3a²+2a=a(a²-3a+2)=a(a-2)(a-1)
a的4次方-a²=a²(a²-1)=a²(a+1)(a-1)
a²+a-2=(a+2)(a-1)
它们的最简公分母是a²(a+2)(a-2)(a+1)(a-1)
1/(a³-3a²+2a)=1/a(a-2)(a-1)=a(a+1)(a+1)/a²(a+2)(a-2)(a+1)(a-1)
2/(a的4次方-a²)=2/a²(a+1)(a-1)=2(a+2)(a-2)/a²(a+2)(a-2)(a+1)(a-1)
-1/(a²+a-2)=-1/(a+2)(a-1)=-a²(a-2)(a+1)/a²(a+2)(a-2)(a+1)(a-1)
1年前
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MZaden
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31-a֮a²-2a+1=1-a ʽӶԲԣԣдȷ1-a֮a²-2a+1=(a-1)²/(1-a)=(1-a)²/(1-a)=1-a дǶԵ ʲô˼