To solve the inequality \( 6x + 1 < 5x - 8 \), we will isolate \( x \).
- Start by subtracting \( 5x \) from both sides:
\[ 6x - 5x + 1 < -8 \]
This simplifies to:
\[ x + 1 < -8 \]
- Next, subtract \( 1 \) from both sides:
\[ x < -8 - 1 \]
This simplifies to:
\[ x < -9 \]
Thus, the solution to the inequality is:
\[ \boxed{x < -9} \]