To solve the equation \( x + 11 = -17 \) for \( x \), you should isolate \( x \) by eliminating the constant on the left side of the equation.
To achieve this, you should subtract 11 from both sides of the equation. Here’s how it looks:
\[ x + 11 - 11 = -17 - 11 \]
This simplifies to:
\[ x = -28 \]
So, the correct answer is to subtract 11.