Question

пожалуйста помогите розвяжіть систему рівннянь методом додавання​

Answer 1

$\displaystyle\bf\\\left \{ {{x^{2} +2xy+y^{2} =1} \atop {6x-7y=19}} \right. \\\\\\\left \{ {{(x+y)^{2}=1} \atop {6x-7y=19}} \right. \\\\1)\\\\\left \{ {{x+y=-1} \ |\cdot7 \atop {6x-7y=19}} \right. \\\\\\+\left \{ {{7x+7y=-7} \ |\cdot7 \atop {6x-7y=19}} \right. \\----------\\13x=12\\\\x=\frac{12}{13} \\\\\\y=-1-x=-1-\frac{12}{13} =-1\frac{12}{13} \\\\2)\\\\\left \{ {{x+y=1} \ |\cdot7 \atop {6x-7y=19}} \right.$

$\displaystyle\bf\\+\left \{ {{7x+7y=7} \ |\cdot7 \atop {6x-7y=19}} \right. \\----------\\13x=26\\\\x=2\\\\y=1-x=1-2=-1\\\\\\Otvet \ : \ \Big(\frac{12}{13} \ ; \ -1\frac{12}{13} \Big) \ \ , \ \ \Big(2 \ ; \ -1\Big)$