Which set notation correctly expresses the solution set to the equation 31−9x=4 ?(1 point)

To solve the equation \(31 - 9x = 4\), we first isolate \(x\).

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

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

The solution set containing this single solution can be expressed in set notation as:
\[
\{ 3 \}
\]

So the correct answer to the question is \(\{ 3 \}\).