Concept:
If two matrices are equal, then their corresponding elements are equal.
Also, the transpose of a matrix is obtained by interchanging rows and columns.
Step 1: Find the transpose of the given matrix.
\[
\begin{bmatrix}
-5 & 6 \\
2 & 3
\end{bmatrix}^{T}
=
\begin{bmatrix}
-5 & 2 \\
6 & 3
\end{bmatrix}
\]
Step 2: Equate corresponding elements.
Given:
\[
\begin{bmatrix}
-5 & 2 \\
6 & 3
\end{bmatrix}
=
\begin{bmatrix}
9y & 6z \\
2x & 3
\end{bmatrix}
\]
So,
\begin{align*}
-5 &= 9y \\
2 &= 6z \\
6 &= 2x \\
3 &= 3
\end{align*}
Step 3: Solve for \( x \).
\[
6 = 2x \Rightarrow x = 3
\]
Conclusion:
The required value of \( x \) is:
\[
x = 3
\]