a) [latex]egin{cases}y=frac{1}{3}x+3 / cdot 3\ y+x=7end{cases}[/latex] [latex]egin{cases}3y=x+9\ y+x=7end{cases}[/latex] [latex]egin{cases}3y-x=9\ y+x=7end{cases}[/latex] +___________ [latex]4y=16 /:4[/latex] [latex]y=4[/latex] [latex]egin{cases}y+x=7\y=4end{cases}[/latex] [latex]egin{cases}4+x=7\y=4end{cases}[/latex] [latex]egin{cases}x=7-4\y=4end{cases}[/latex] [latex]egin{cases}x=3\y=4end{cases}[/latex] Do rozwiązania graficznego: [latex]egin{cases}y=frac{1}{3}x+3\ y+x=7end{cases}[/latex] [latex]egin{cases}y=frac{1}{3}x+3\ y=-x+7end{cases}[/latex] ====================== b) [latex]egin{cases}y=-2x+2\ 4y+3x=-12end{cases}[/latex] [latex]egin{cases}y+2x=2 / cdot (-4)\ 4y+3x=-12end{cases}[/latex] [latex]egin{cases}-4y-8x=-8\ 4y+3x=-12end{cases}[/latex] +___________ [latex]-5x=-20 /:(-5)[/latex] [latex]x=4[/latex] [latex]egin{cases}x=4\y=-2x+2end{cases}[/latex] [latex]egin{cases}x=4\y=-2 cdot 4+2end{cases}[/latex] [latex]egin{cases}x=4\y=-8+2end{cases}[/latex] [latex]egin{cases}x=4\y=-6end{cases}[/latex] Do rozwiązania graficznego: [latex]egin{cases}y=-2x+2\ 4y=-3x-12 /:4end{cases}[/latex] [latex]egin{cases}y=-2x+2\ y=- frac{3}{4} x-3end{cases}[/latex]
