1樓：
見圖公式編輯器做的花了點時間
2樓：匿名使用者
(a²+3)/(a²-1)-(a+1)(a-1)+1=[a²+3-(a+1)²+a²-1]/(a²-1)=(a²-2a+1)/(a²-1)
=(a-1)²/(a+!)(a-1)
=(a-1)/(a+1)
原式=1/(x-2)²+1/[2(x+2)]-x/[2(x+2)(x-2)]
=1/(x-2)²+(x-2-2x)/[2(x+2)(x-2)]=1/(x-2)²-(x+2)/[2(x+2)(x-2)]=1/(x-2)²-1/[2(x-2)]
=[2-(x-2)]/[2(x-2)²]
=(4-x)/[2(x-2)²]
原式=×(xy)/(y-1)
=[1/(x-y)-y/(x-y)]×(xy)/(y-1)=(1-y)/(x-y)×(xy)/(y-1)=xy/(y-x)
3樓：老黃知識共享
第一題原式=[(a^2+3)-(a^2+2a+1)]/(a^2-1)-1=(-2a+2)/(a^2-1)-1=-2/(a+1)-1=(-2-a-1)/(a+1)=-(a+3)/(a+1)
第二題原式=1/(x-2)^2-x/[(x+2)(x-2)]+1/[2(x+2)]
=2(x+2)/[2(x+2)(x-2)^2]-2x(x-2)/[2(x+2)(x-2)^2]+(x-2)^2/[2(x+2)(x-2)^2]
=[2(x+2)-2x(x-2)+(x-2)^2]/[2(x+2)(x-2)^2]
=(2x+4-2x^2+4x+x^2-4x+4)/[2(x+2)(x-2)^2]
=(-x^2+2x+8)/[2(x+2)(x-2)^2]
=-(x+2)(x-4)/[2(x+2)(x-2)^2]
=-(x-4)/[2(x-2)^2]
第三題原式=*xy/(y-1)
=[1/(x-y)-y/(x-y)]*xy/(y-1)
=-(y-1)/(x-y)*xy/(y-1)
=-xy/(x-y)
4樓：匿名使用者
(a²+3)/(a²-1)-(a+1)/(a-1)+1
=(a²+3)/(a+1)(a-1)-(a+1)²/(a+1)(a-1)+(a²-1)/(a+1)(a-1)
=(a²+3-a²-2a-1+a²-1)/(a+1)(a-1)
=(a²-2a+1)/(a+1)(a-1)
=(a-1)²/(a+1)(a-1)
=(a-1)/(a+1)
1/(x²-4x+4)-x/(x²-4)+1/(2x+4)
=1/(x-2)²-x/(x-2)(x+2)+1/2(x+2)
=[2(x+2)-2x(x-2)+(x-2)²]/2(x+2)(x-2)²
=(2x+4-2x²+4x+x²-4x+4)/2(x+2)(x-2)²
=(-x²+2x+8)/2(x+2)(x-2)²
=-(x-4)(x+2)/2(x+2)(x-2)²
=-(x-4)/2(x-2)²
[(x-y)/(x²-2xy+y²)-(xy+y²)/(x²-y²)]*xy/(y-1)
=[(x-y)/(x-y)²-y(x+y)/(x-y)(x+y)]*xy/(y-1)
=[(1/(x-y)-y/(x-y)]*xy/(y-1)
=(1-y)/(x-y)*xy/(y-1)
=-xy/(x-y)
5樓：好
第一題(a^2+3)/(a^2-1)-(a+1)/(a-1)+1
=(a^2+3)/(a^2-1)-(a+1)(a+1)/(a-1)(a+1)+(a^2-1)/(a^2-1)
=(a^2+3)/ (a^2-1)-(a+1)^2/(a^2-1)+(a^2-1)/(a^2-1)
=(a^2+3-a^2-2a-1+a^2-1)/(a^2-1)
=(a^2-2a+1)/(a^2-1)
=(a-1)^2/(a+1)(a-1)
=(a-1)/(a+1)
第二題1/（x^2-4x+4）-x/（x^2-4）+1/(2x+4)
=1/(x-2)^2+x/(x-2)(x+2)-1/2(x+2)
=[2(x+2)+2x(x-2)-(x-2)^2]/2(x+2)(x-2)^2
=x(x+2)/2(x+2)(x-2)^2
=x/2(x-2)^2
第三題[（x-y）/(x^-2xy+y^2)-(xy+y^2)/(x^2-y^2)]*xy/(y-1)
=[(x-y)/(x-y)^2-y(x+y)/(x+y)(x-y)]*xy/(y-1)
=[1/（x-y)-y/(x-y)]*xy/(y-1)
=[(1-y)/(x-y)][xy/(y-1)]
=-xy/(x-y).
6樓：
第一題=(a^2+3-a^2-2a-1+a^2-1)/a^2-1=（a-1）^2/(a-1)(a+1)
=a-1/a+1
第二題：
=[2(x+2）-2x(x-2)+(x-2)^2]/2(x-2)^2(x+2)
=(4-x)/2(x-2)^2
第三題：
=[(1/x-y)-(y/x-y)]*(xy/y-1)=xy/y-x
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