# What is the domain of f(x)=(x^2+2x)/(x+1) ?

${D}_{f} = \left(- \infty , - 1\right) \cup \left(- 1 , + \infty\right)$
Given function is defined when we can divide with $x + 1$ so:
$x + 1 \ne 0$
$x \ne - 1$
${D}_{f} = \left(- \infty , - 1\right) \cup \left(- 1 , + \infty\right)$