Question

初二分式题

已知x^2-1=0，求代数式(x-1)^2/(x^2-1)+x^2/(x+1)

Answer 1

原式=(x-1)^2/(x+1)(x-1)+(x^2)(x-1)/(x+1)(x-1)
=(x-1)^2/(x^2-1)+(x^2)(x-1)/(x^2-1)
因为x^2-1=0
所以原式=(x-1)^2/0+(x^2)(x-1)/0
所以原式无意义

Answer 2

解：由已知 x^2-1=0，
x^2=1
x=土1 ，
当x1=1 时，
则：(x-1)^2/(x^2-1)+x^2/(x+1)=1/2 ;
当x2=-1时，分式的分母为0，分式无意义。

Answer 3

x^2-1=0
分式无意义

(x-1)^2/(x^2-1)+x^2/(x+1)
=(x-1)^2/(x-1)(x+1)+x^2/(x+1)
=(x-1)/(x+1)+x^2/(x+1)
=(x-1+x^2)/(x+1)

Answer 4

1/2