1.（x^2+x）/(x^2-1) 2.(x^2-9)/(x^2-61.（x^2+x）/(x^2-1)2.(x^2-9)/(x^2-6x+9)3.先化简后求值 x=5.(x^2-8x+16)/(x^2-16)都是分数来的

1.（x^2+x）/(x^2-1) 2.(x^2-9)/(x^2-61.（x^2+x）/(x^2-1)2.(x^2-9)/(x^2-6x+9)3.先化简后求值 x=5.(x^2-8x+16)/(x^2-16)都是分数来的
1.（x^2+x）/(x^2-1) 2.(x^2-9)/(x^2-6
1.（x^2+x）/(x^2-1)
2.(x^2-9)/(x^2-6x+9)
3.先化简后求值 x=5.(x^2-8x+16)/(x^2-16)
都是分数来的

1.（x^2+x）/(x^2-1) 2.(x^2-9)/(x^2-61.（x^2+x）/(x^2-1)2.(x^2-9)/(x^2-6x+9)3.先化简后求值 x=5.(x^2-8x+16)/(x^2-16)都是分数来的
1.（x^2+x）/(x^2-1)=x(x+1)/(x-1)(x+1)=x/(x-1)
2.(x^2-9)/(x^2-6x+9)
=(x-3)(x+3)/(x-3)²
=(x+3)/(x-3)
3.(x^2-8x+16)/(x^2-16)
=(x-4)²/(x+4)(x-4)
=(x-4)/(x+4)
=(5-4)/(5+1)
=1/9