Respostas

2014-04-13T12:21:05-03:00
  \left[\begin{array}{cc}x-1&3+5\\4+8&y+y\end{array}\right] =    \left[\begin{array}{cc}4&8\\12&-6\end{array}\right]\\
  \left[\begin{array}{cc}x-1&8\\12&2y\end{array}\right] =    \left[\begin{array}{cc}4&8\\12&-6\end{array}\right]\\
x-1 = 4\\
x = 5\\
2y = -6\\
y = -3

Agradeço se avaliar a resposta der um obrigado.