另类精彩
花朵
共回答了12个问题采纳率:100% 举报
1.1/(x+1)+1/(x-1)-(x^2+1)/(x^2-1)=(x-1)/(x^2-1)+(x+1)/(x^2-1)-(x^2+1)/(x^2-1)=2x/(x^2-1)-(x^2+1)/(x^2-1)=-(x-1)^2/((x+1)(x-1))=-(x-1)/(x+1)=(1-x)/(1+x)
2.关键是要知道x^2-x-6的拆分
x^2 -x -6
x -3
x 2
即x^2=x*x,-6=-3*2,-x=-3x+2x
所以x^2-x-6=(x-3)(x+2)
(x^2-4)/(x^2-x-6)=((x+2)*(x-2))/((x+2)*(x-3))=(x-2)/(x-3)
原式=((x-2)/(x-3)+(x+2)/(x-3))/((x+1)/(x-3))=2x/(x-3)*(x-3)/(x+1)=2x/(x+1)
1年前
7