怎么做 这几道题``给分

来源：百度知道 编辑：UC知道 时间：2024/07/02 14:13:27
1.[(x/(x-2))-(x/(x+2))]*[(2-x)/x]

2.1-[(a-(1/(1-a))^2]/[(a^2-a+1)/(a^2-2a+1)

3.[((x+2)/(x^2-2x))-((x-1)/(x^2-4x+4))]/((x-4)/x)

尽量做吧```括号被偶加多了```方便大家清楚些 麻烦了

1.[(x/(x-2))-(x/(x+2))]*[(2-x)/x]
=[(x*(x+2)-x*(x-2))/((x-2)*(x+2))]*[(2-x)/x]
=[4x/((x-2)*(x+2))]*[-(x-2)/x]
=-4/(x+2)
2.1-[(a-(1/(1-a))^2]/[(a^2-a+1)/(a^2-2a+1)]
=1-[((a*(1-a)-1)/(-(a-1)))^2]/[(a^2-a+1)/(a-1)^2]
=1-[-(a^2-a+1)/(-(a-1)))^2]/[(a^2-a+1)/(a-1)^2]
=1-[(a^2-a+1)^2/(a-1)^2]*(a-1)^2/(a^2-a+1)
=1-(a^2-a+1)
=1-a^2+a-1)
=a(1-a)
3.[((x+2)/(x^2-2x))-((x-1)/(x^2-4x+4))]/((x-4)/x)
=[((x+2)/x(x-2))-((x-1)/(x-2)^2)]/((x-4)/x)
=[((x+2)*(x-2)-x(x-1))/(x(x-2)^2)]/((x-4)/x)
=[(x^2-4-x^2+x)/(x(x-2)^2)]/((x-4)/x)
=[(x-4)/(x(x-2)^2)]*(x/(x-4))
=1/((x-2)^2)