Step 1 :Given the matrices \(\left[\begin{array}{rr} x & 5 y \ z & 6 \end{array}\right]\) and \(\left[\begin{array}{rr} 12 & 15 \ 7 & 6 \end{array}\right]\), we need to find the values of \(x\), \(y\), and \(z\) that make these matrices equal.
Step 2 :For two matrices to be equal, their corresponding elements must be equal. This gives us the system of equations: \(x = 12\), \(5y = 15\), and \(z = 7\).
Step 3 :Solving the first equation gives \(x = 12\).
Step 4 :Solving the second equation gives \(y = 3\).
Step 5 :Solving the third equation gives \(z = 7\).
Step 6 :Final Answer: The solution to the system of equations is \(x=\boxed{12}\), \(y=\boxed{3}\), and \(z=\boxed{7}\).