To express the solution set for the equation \( 31 - 9x = 4 \), we first need to solve for \( x \).
-
Subtract 31 from both sides: \[ -9x = 4 - 31 \] \[ -9x = -27 \]
-
Divide by -9: \[ x = 3 \]
Now, to express the solution set:
- The solution \( x = 3 \) is a specific number, so we can represent the solution set as \( { 3 } \).
Therefore, the correct set notation that expresses the solution set is: \[ { 3 } \]
So the answer is {3}.