Odpowiedź:
[tex]+\begin{cases}x+y=8\\x-y=2\end{cases}\\-------\\2x=10\ \ /:2\\x=5\\\\\\5+y=8\\\\y=8-5\\\\y=3\\\\\begin{cases}x=5\\y=3\end{cases}[/tex]
[tex]\begin{cases}3x-2y=-9\\2x+y=1\ \ /*2\end{cases}\\\\\\+\begin{cases}3x-2y=-9\\4x+2y=2\end{cases}\\---------\\7x=-7\ \ /:7\\x=-1\\\\\\2*(-1)+y=1\\\\-2+y=1\\\\y=1+2\\\\y=3\\\\\begin{cases}x=-1\\y=3\end{cases}[/tex]
[tex]\begin{cases}x+y=6\ \ /*(-2)\\3x+2y=20\end{cases}\\\\\\+\begin{cases}-2x-2y=-12\\3x+2y=20\end{cases}\\---------\\x=8\\\\\\8+y=6\\\\y=6-8\\\\y=-2\\\\\begin{cases}x=8\\y=-2\end{cases}[/tex]
[tex]\begin{cases}2x-3y=14\ \ /*2\\5x+2y=16\ \ /*3\end{cases}\\\\\\+\begin{cases}4x-6y=28\\15x+6y=48\end{cases}\\---------\\19x=76\ \ /:19\\x=4\\\\\\2*4-3y=14\\\\8-3y=14\\\\-3y=14-8\\\\-3y=6\ \ /:(-3)\\\\y=-2\\\\\begin{cases}x=4\\y=-2\end{cases}[/tex]
