A problem of higher number about limit lim [1/(1-x)-3/(1-x)³] x→1

A problem of higher number about limit lim [1/(1-x)-3/(1-x)³] x→1

First of all, you have made a mistake in the brackets, change them, and then divide them all
1/(1-x)-3/(1-x³)
=(x-1)(x+2)/[(1-x)(1+x+xx)]
=-(x+2)/(1+x+xx)
So when X - > 1, the limit is - 1