To solve the equation \( x + 1 = 0 \), you need to isolate the variable \( x \). Here are the steps:

1. Start with the equation:
\[
x + 1 = 0
\]

2. Subtract 1 from both sides of the equation to isolate \( x \):
\[
x + 1 - 1 = 0 - 1
\]

3. Simplify both sides:
\[
x = -1
\]

So, the solution to the equation \( x + 1 = 0 \) is:
\[
x = -1
\]