Let δ be a very small positive quantity.
When x=1-δ, x1/(1-x)=(1-δ)/δ=1/δ-1. As δ→0, 1/δ→∞ (limit approached from the left).
When x=1+δ, x1/(1-x)=(1+δ)/(-δ)=-1/δ+-1. As δ→0, 1/δ→-∞ (limit approached from the right).
The two limits are dissimilar, so limit as x→1 is indeterminate.
As x→1- (x approaches 1 from the left, the negative side) the limit is infinity.