Question

已知2(x^2-1)/x+1-6(x-1)/x^2-1，设x^2+1/x-1=y，则原分式可变形为,

如题~谢谢
题没输错误啊

Answer 1

应该是(x²-1)/(x-1)=y
所以(x-1)/(x²-1)=1/y
所以原式=2y-6/y

Answer 2

1.(x+2)²=2x+4
(x+2)²-2(x+2)=0
(x+2)(x+2-2)=0
x(x+2)=0
x=0,x=-2

2.4(x-3)²-x(x-3)=0
(x-3)(4x-12-x)=0
3(x-3)(x-4)=0
x=3,x=4

3.(x+1)(x-3)=5
x²-2x-3-5=0
(x-4)(x+2)=0
x=4,x=-2

4.3x²-x=0
x(3x-1)=0
x=0,x=1/3

这几题随便用什么方法都可以：
1.4(x-3)²=7
(x-3)²=7/4
x-3=±√7/2
x=(6-√7)/2,x=(6+√7)/2

2.-3x²+2x+5=0
3x²-2x-5=0
(3x-5)(x+1)=0
x=5/3,x=-1

3.(2x-3)²=4x²-9
(2x-3)²-(2x-3)(2x+3)=0
(2x-3)(2x-3-2x-3)=0
-6(2x-3)=0
x=3/2

4.x²-4x-1=0
x²-4x+4=1+4=5
(x-2)²=5
x-2=±√5
x=2-√5,x=2+√5