The coefficients of x and y in the first equation are 3 and -4, respectively.
The coefficients of x and y in the second equation are 1 and 6, respectively.
The coefficient matrix lists these coefficients in order on successive rows, so it will be ...
![\left[\begin{array}{cc}3&-4\\1&6\end{array}\right]](https://img.qammunity.org/2019/formulas/mathematics/college/hurc8z2yguz16lo9euvp68yo5sav2jsqfd.png)