The system of equations is represented in matrix form as \(AX = B\), where:
$$
\begin{align_}
A &= \begin{bmatrix} 1 & 2 & 0 \\ 0 & 3 & -4 \\ 1 & 6 & 1 \end{bmatrix},
X &= \begin{bmatrix} x \\ y \\ z \end{bmatrix},
B &= \begin{bmatrix} 12 \\ 25 \\ 20 \end{bmatrix}
\end{align_}
$$
Step 2: Determinant Check
The determinant of matrix \(A\) is 19.
Step 3: Solution Method
Since the determinant is non-zero, the system has a unique solution.
The solution is found using the inverse of matrix \(A\) to find \(X = A^{-1}B\).
The solution is \(x = 6, y = 3, z = -4\).
Final Answer:
The unique solution to the system of equations is \(x = 6, y = 3, z = -4\).