Odpowiedź:
[tex]1.\\\\\begin{cases}3x+y=2\\x-y=6\end{cases}\\\\\\\begin{cases}y=2-3x\\x-y=6\end{cases}\\\\\\x-(2-3x)=6\\\\x-2+3x=6\\\\4x=6+2\\\\4x=8\ \ /:4\\\\x=2\\\\\\y=2-3*2=2-6=-4\\\\\begin{cases}x=2\\y=-4\end{cases}[/tex]
[tex]2.\\\\\begin{cases}3(x-y)-4(x-y)=-5\\6-x=2(x-3y)-18\end{cases}\\\\\\\begin{cases}3x-3y-4x+4y=-5\\6-x=2x-6y-18\end{cases}\\\\\\\begin{cases}-x+y=-5\\-x-2x+6y=-18-6\end{cases}\\\\\\\begin{cases}-x+y=-5\\-3x+6y=-24\ \ /:(-3)\end{cases}\\\\\\\begin{cases}-x+y=-5\\x-2y=8\end{cases}\\\\\\\begin{cases}y=-5+x\\x-2y=8\end{cases}\\\\\\x-2(-5+x)=8\\\\x+10-2x=8\\\\-x=8-10\\\\-x=-2\ \ /*(-1)\\\\x=2\\\\\\y=-5+2=-3\\\\\begin{cases}x=2\\y=-3\end{cases}[/tex]
[tex]3.\\\\\begin{cases}4x-y=2\\\frac{1}{2}y=2(x-1)\ \ \end{cases}\\\\\\\begin{cases}4x-y=2\\\frac{1}{2}y=2x-2\ \ /*2\end{cases}\\\\\\\begin{cases}4x-y=2\\y=4x-4\end{cases}\\\\\\4x-(4x-4)=2\\\\4x-4x+4=2\\\\4=2\\\\Uklad\ \ r\'owna\'n\ \ sprzeczny\ \ nie\ \ ma\ \ rozwiazania[/tex]
