[tex]\Large\boxed{\begin{array}{l}\sf a_{11}=1-4\cdot1=1-4=-3\\\sf a_{12}=1-4\cdot2=1-8=-7\\\sf a_{21}=2-4\cdot1=2-4=-2\\\sf a_{22}=2-4\cdot2=2-8=-6\\\sf a_{31}=3-4\cdot1=3-4=-1\\\sf a_{32}=3-4\cdot2=3-8=-5\\\\\sf A=\begin{bmatrix}\sf-3&\sf-7\\\sf-2&\sf-6\\\sf-1&\sf-5\end{bmatrix}\end{array}}[/tex]
