which set notation correctly expresses the solution set of the equation 31 minus 9X equals four

To express the solution set of the equation \( 31 - 9x = 4 \) using set notation, we first need to solve for \( x \).

1. Start with the equation:
\[
31 - 9x = 4
\]

2. Subtract 31 from both sides:
\[
-9x = 4 - 31
\]
\[
-9x = -27
\]

3. Divide both sides by -9:
\[
x = \frac{-27}{-9}
\]
\[
x = 3
\]

Now that we have found the solution \( x = 3 \), we can express this in set notation. The solution set containing this single value can be expressed as:

\[
\{3\}
\]

Thus, the correct set notation for the solution set of the equation is \( \{3\} \).