1.a为何值时,分式方程x+1分之3a+1=a无解?2.已知x的平方-2=0,求代数式（x-1）的平方除以x平方-1+x

1.
(3a+1)/(x+1)=a
3a+1=ax+a
ax=2a+1
x=2+1/a
x≠-1
2+1/a≠-1
a≠-1/3
a=-1/3时,分式方程x+1分之3a+1=a无解
2.
x^2-2=0,x^2-1=1,x=±2
(x-1)^2/(x^2-1)+x^2/(x+1)=(x-1)^2/(x^2-1)+x^2*(x-1)/(x^2-1)
=(x-1)^2/1+x^2*(x-1)/1=x^2-2x+1+x^3-x^2=x^3-2x+1=x*(x^2-1)+1
=x*1+1=x+1
x=+2时,上式=3
x=-2时,上式=-1