求几道数学题啦,

来源:学生作业帮助网 编辑:作业帮 时间:2024/03/29 22:53:54
求几道数学题啦,

求几道数学题啦,
求几道数学题啦,

求几道数学题啦,
21.原式=2/(a-1)-(a+1)/(a-1)=[2-a-1]/(a-1)=-(a-1)/(a-1)=-1
22.原式=[x²-2x+1]/(x+1) *(x²-1)/[x²-2x+1]=(x²-1)/(x+1)=x-1
23.(1)原式=2-1+4=5
(2)原式=(a²-1)/a*a/(a-1)²=(a+1)(a-1)/(a-1)²=(a+1)/(a-1)=1-1/(a-1)

21题(2a+2)/(a-1)÷﹙a+1﹚=2*(a+1)/(a+1)÷(a-1)=2/(a-1)=2(a-1)÷(a-1)²;
原式=2(a-1)÷(a-1)²+﹙a²-1﹚÷﹙a-1)²=[2(a-1)+﹙a²-1﹚]÷﹙a-1)²=﹙a²+2a-3﹚/﹙a-1﹚²=
﹙a+3﹚﹙a-1﹚/(a-1...

全部展开

21题(2a+2)/(a-1)÷﹙a+1﹚=2*(a+1)/(a+1)÷(a-1)=2/(a-1)=2(a-1)÷(a-1)²;
原式=2(a-1)÷(a-1)²+﹙a²-1﹚÷﹙a-1)²=[2(a-1)+﹙a²-1﹚]÷﹙a-1)²=﹙a²+2a-3﹚/﹙a-1﹚²=
﹙a+3﹚﹙a-1﹚/(a-1)²=﹙a+3﹚/(a-1)
22题=[x(x-1)/(x+1)]÷﹛﹙x-1﹚²÷[﹙x+1﹚(x-1)]﹜=[x(x-1)/(x+1)]×﹛[﹙x+1﹚(x-1)]÷﹙x-1﹚²﹜=x

收起

21.原式= 2(a+1)/ (a-1) X 1/(a+1) - (a+1)*(a-1)/ (a-1)²
= 2/(a-1)- (a+1)/(a-1)
=1-a/(a-1)
= -1
22.原式= [( x²+x)/x+1 - ...

全部展开

21.原式= 2(a+1)/ (a-1) X 1/(a+1) - (a+1)*(a-1)/ (a-1)²
= 2/(a-1)- (a+1)/(a-1)
=1-a/(a-1)
= -1
22.原式= [( x²+x)/x+1 - 2X/x+1]÷(x-1 )²/(x+1)*(x-1)
=x(x-1)/(x+1)* (x+1)/(x-1)
=X
23.1原式= 2-1+4
23.2原式= (a²-1)/a ÷ (a-1)² /a
=(a+1)*(a-1) 分之 (a-1)²
=a+1 / a-1
还等于 1+ 2/a-1
欢迎追问

收起