[tex] \left \{ {{6x-4y=54} \atop {-9x+2y=-6\ \ | *2}} \right. \\\\
\left \{ {{6x-4y=54} \atop {-18x+4y=-12}} \right. \\+-----\\addition\ method\\\\
-12x=42\ \ \ | divide\ by\ -12\\
x=-3.5\\\\
2y=-6+9x\\
y=\frac{-6+9x}{2}=\frac{-6+31.5}{2}=\frac{25.5}{2}=12.75\\\\
\left \{ {{y=12.75} \atop {x=-3.5}} \right. [/tex]
