y'=(x/x-1)'=((x-1-x)/(x-1)^2)=-1/(-2-1)^2=-1/9
y'= [ 1*(x-1)-x*1 ] / (x-1)^2 = [x-1-x]/(x-1)^2 = -1/(x-1)^2
y'(-2) = -1/(-2-1)^2 = -1/9
y'=(x/x-1)'=((x-1-x)/(x-1)^2)=-1/(-2-1)^2=-1/9
y'= [ 1*(x-1)-x*1 ] / (x-1)^2 = [x-1-x]/(x-1)^2 = -1/(x-1)^2
y'(-2) = -1/(-2-1)^2 = -1/9