Answer:
(a). [tex]A_{x}[/tex] = [tex]\left[\begin{array}{cc}12&-4\\66&6\end{array}\right][/tex]
Step-by-step explanation:
[tex]\left \{ {{5x-4y=12} \atop {3x+6y=66}} \right.[/tex]
A = [tex]\left[\begin{array}{cc}5&-4\\3&6\end{array}\right][/tex]
[tex]A_{x}[/tex] = [tex]\left[\begin{array}{cc}12&-4\\66&6\end{array}\right][/tex]
[tex]A_{y}[/tex] = [tex]\left[\begin{array}{cc}5&12\\3&66\end{array}\right][/tex]
