Answer
$-\infty.$
Work Step by Step
We have $$
\lim _{x \rightarrow 1^-} \frac{3-x}{x-1}= -\infty.
$$
We know that the limit from the left will be negative infinity because the numerator will be positive (since 3 is greater than 1), while the denominator will be negative and arbitrarily close to zero.