To solve the equation \( x^2 + 9 = 45 \), we first isolate \( x^2 \):
\[ x^2 = 45 - 9 \] \[ x^2 = 36 \]
Next, we take the square root of both sides:
\[ x = \pm 6 \]
This means the solutions are \( x = 6 \) and \( x = -6 \). Therefore, the solution set is \( {-6, 6} \).
Now we can evaluate the responses:
- Trey says the solution is {6}. (Incorrect)
- Amelia says the solution is {-6, 6}. (Correct)
- Cho says the solution is {-6}. (Incorrect)
The correct answer is Amelia.