Solve this following

If $\left[\begin{array}{cc}x & 6 \\ -1 & 2 w\end{array}\right]+\left[\begin{array}{cc}4 & x+y \\ z+w & 3\end{array}\right]=3\left[\begin{array}{cc}x & y \\ z & w\end{array}\right]$, find the values of $x, y, z, w$.