Can someone help me with this question this is for a assignment

In order to find the solution of the equation, we can do the following steps:
[tex]\begin{gathered} \sqrt{x}-9=-6\\ \\ \sqrt{x}=-6+9\\ \\ \sqrt{x}=3\\ \\ (\sqrt{x})^2=3^2\\ \\ x=9 \end{gathered}[/tex]Therefore the correct option is C.