To solve the inequality \( x - 91 < 18 \), we will isolate \( x \).
1. Start by adding 91 to both sides of the inequality:
\[
x - 91 + 91 < 18 + 91
\]
2. This simplifies to:
\[
x < 109
\]
So, the solution to the inequality is:
\[
x < 109
\]
This means that \( x \) can take on any value that is less than 109.