a) [latex]egin{cases}x+2y=11 qquad /cdot (-5) \ 5x-3y=3 end{cases} \ +egin{cases} -5x-10y=-55 \ 5x-3y=3end{cases} \ \ -13y=-52 qquad /:(-13) \ \ y=4 \ \ x+2y=11 \ \ x+8=11 \ \ x=3 \ \ egin{cases} x=3 \ y=4end{cases}[/latex] b) [latex]+egin{cases} x+y=5 \ x-y=1end{cases} \ 2x=6 qquad /:2 \ x=3 \ \ x+y=5 \ 3+y=5 \ y=2 \ \ egin{cases}x=3 \ y=2 end{cases}[/latex] c) [latex]egin{cases}x-y=5 qquad /cdot 4 \ 3x+4y=8 end{cases} \ \ +egin{cases} 4x-4y=20 \ 3x+4y=8end{cases} \ \ 7x=28 qquad /:7 \ x=4 \ \ x-y=5 \ 4-y=5 \ y=-1 \ \ egin{cases} x=4 \ y=-1end{cases}[/latex] d) [latex]egin{cases} 3x+y=5 \ x-2y=-3 qquad /cdot (-3)end{cases} \ \ +egin{cases}3x+y=5 \ -3x+6y=9 end{cases} \ \ 7y=14 qquad /:7 \ y=2 \ \ x-2y=-3 \ x-4=-3 \ x=1 \ \ egin{cases} x=1\y=2end{cases}[/latex] Dopytuj w komentarzach jeśli nie rozumiesz
a) x + 2y = 11 / ∙ 3 5x - 3y = 3 / ∙ 2 3x + 6y = 33 10x - 6y = 6 13x = 39 / : 13 x = 3 3 + 2y = 11 / -3 2y = 8 / :2 y = 4 b) x + y = 5 x - y = 1 2x = 6 / : 2 x = 3 3 + y = 5 / -3 y = 2 c) x - y = 5 / ∙ 4 3x + 4y = 8 4x - 4y = 20 3x + 4y = 8 7x = 28 / : 7 x = 4 4 - y = 5 / - 4 -y = 1 / ∙ (-1) y = -1 d) 3x + y = 5 / ∙ 2 x - 2y = -3 6x + 2y = 10 x - 2y = -3 7x = 7 / : 7 x = 1 3 ∙ 1 + y = 5 / -3 y = 2 Liczę na naj :D
