Answer
$\color{blue}{(-\infty, -1) \cup (-1, +\infty)}$
Work Step by Step
The denominator of a rational expression is not allowed to be equal to zero as it will make the expression undefined.
Thus,
$x+1 \ne0
\\x\ne-1$
Therefore, the domain of the given rational expression is the set of real numbers except $-1$.
In interval notation, the domain is:
$\color{blue}{(-\infty, -1) \cup (-1, +\infty)}$
