Hello,
[tex]$ \left \{ {{2x-y=1} \atop {3x+2y=12}} \right. $[/tex]
[tex]\Delta= \left[\begin{array}{cc}2&-1\\3&2\end{array}\right] =4+3=7\\
\Delta_1= \left[\begin{array}{cc}1&-1\\12&2\end{array}\right] =2+12=14\\
\Delta_2= \left[\begin{array}{cc}2&1\\3&12\end{array}\right] =24-3=21\\\\
\left \{x= \dfrac{\Delta_1}{\Delta} = \dfrac{14}{7} =2} \atop {
y= \dfrac{\Delta_2}{\Delta} = \dfrac{21}{7} =3} \right
[/tex]
