Calculate the Following Limit(s) If They Exist $\lim _ { x \rightarrow 1 }$

Short Answer

Calculate the following limit(s) if they exist.
- $\lim _ { x \rightarrow 1 }$ $\frac { x ^ { 6 } - 1 } { x ^ { 3 } - 1 }$ Enter your answer as just an integer or a fraction in lowest terms, or the words "does not exist".