(3x-3)/(x^2-1)÷3x/(x+1)-1/(x-1)
=3(x-1)/(x+1)(x-1)*(x+1)/3x-1/(x-1)
=1/x-1/(x-1)
=(x-1-x)/x(x-1)=1/x(1-x)=1/[2*(-1)=-1/2
(x^2+2x+1)/（x+2）÷(x^2-1)/(x-1)-1/(x+2)
=(x+1)^2/(x+2)*(x-1)/(x+1)(x-1)-1/(x+2)
=(x+1)/(x+2)-1/(x+2)
=x/(x+2)=1/2/(1/2+2)=1/2*2/5=1/5