Odpowiedź:
[tex]\begin{cases}-2(x+1)+3(x+y)=-2\\x+1+2(y-4)=13\end{cases}\\\\\\\begin{cases}-2x-2+3x+3y=-2\\x+1+2y-8=13\end{cases}\\\\\\\begin{cases}x+3y=-2+2\\x-7+2y=13\end{cases}\\\\\\\begin{cases}x+3y=0\\x+2y=13+7\end{cases}\\\\\\\begin{cases}x=-3y\\x+2y=20\end{cases}\\\\\\-3y+2y=20\\\\-y=20\ \ /*(-1)\\\\y=-20\\\\\\x=-3*(-20)=60\\\\\\\begin{cases}x=60\\y=-20\end{cases}[/tex]
