Answer :
[tex]\left\{\begin{array}{ccc}x+3y=14\\6x+3y=-6&/\cdot(-1)\end{array}\right\\+\left\{\begin{array}{ccc}x+3y=14\\-6x-3y=6\end{array}\right\\-----------\\.\ \ \ \ \ -5x=20\ \ \ \ /:(-5)\\.\ \ \ \ \ \ \ \ \ \ x=-4\\\\-4+3y=14\\3y=14+4\\3y=18\ \ \ \ /:3\\y=6\\\\Solution:x=-4\ and\ y=6[/tex]
