Question

求这些题的过程和答案，谢谢！

Answer 1

(3)解：原式=a²/(a-1)-(a+1)
=a²/(a-1)-(a+1)(a-1)/(a-1)
=［a²-(a+1)(a-1)］/(a-1)
=（a²-a²+1）/(a-1)
=1/(a-1)
(4)解：[（x+2)/(x²－2x） -1/（x-2）] ÷ (2/x)
=[(x+2-x)/(x²－2x） ] × (x/2)
=2/[x(x-2)] × (x/2)
=1/(x-2)

追答

后2题

解：(1+1/x-1)÷x/x2-1
=x/(x-1)÷x/(x^2-i)
=(x^2-1）/(x-1)
=x+1
=-2+1
=-1

解=2(x+3)/(x-2)²*(x-2)/x(x+3)-1/(x2-2)
=2/x(x-2)-1/(x-2)
=(2-x)/x(x-2)
=-1/x
=-1/-√2=1/√2