Odpowiedź:
[tex]Metoda\ \ podstawiania\\\\\begin{cases}4x+y=5\\2x+3y=13\end{cases}\\\\\\\begin{cases}y=5-4x\\2x+3y=13\end{cases}\\\\\\2x+3(5-4x)=13\\\\2x+15-12x=13\\\\-10x=13-15\\\\-10x=-2\ \ /:(-10)\\\\x=0,2\\\\\\y=5-4\cdot0,2=5-0,8=4,2\\\\\begin{cases}x=0,2\\y=4,2\end{cases}[/tex]
[tex]Metoda\ \ przeciwnych\ \ wsp\'olczynnik\'ow\\\\\begin{cases}4x+y=5\ \ /\cdot(-3)\\2x+3y=13\end{cases}\\\\\\+\begin{cases}-12x-3y=-15\\2x+3y=13\end{cases}\\----------\\-10x=-2\ \ /:(-10)\\x=0,2\\\\\\2\cdot0,2+3y=13\\\\0,4+3y=13\\\\3y=13-0,4\\\\3y=12,6\ \ /:3\\\\y=4,2\\\\\begin{cases}x=0,2\\y=4,2\end{cases}[/tex]
