jak obliczyć plisss na jutro !! [latex] left { {{2x+y=12} atop {2x-6y=26}} ight. [/latex] [latex] left { {{2y-x=4} atop {3y+x=6}} ight. [/latex] [latex] left { {{4x-y=17} atop {x+y=8}} ight.

[latex]1)\\ egin{cases} 2x+y=12 /*6 \ 2x-6y=26 end{cases}\\ egin{cases}12x+6y=72 \ 2x-6y=26 end{cases}\+ -------\ 14x=98 /:14\x=7\\2x+y=12\y=-2x+12\y=-2*7+12=-14+12=2\\ egin{cases} x=7 \ y=-2 end{cases}[/latex] [latex]2)\\ egin{cases} 2y-x=4 \ 3y+x=6 end{cases}\+-------\ 5y=10 /:5\y=2\\ x=2y-4 \x=2*2-4=4-4=0\\egin{cases} x=0 \ y=2 end{cases}[/latex] [latex]3)\\ egin{cases} 4x-y=17 \ x+y=8 end{cases}\+ --------\ 5x=25 /:5\x=5\\ x+y=8\y=8-x\y=8-5\y=3\\egin{cases} x=5 \ y=3 end{cases}[/latex]