Алгебра 1 год назад evigi

Розв'язати систему рівнянь
{2х+у=–12
{х²+у²-2ху=9

Ответ
1
misakabys
Вот решение:
Надіюсь, тебе поможет.
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Ответ
1
Universalka

\displaystyle\bf\\\left \{ {{2x+y=-12} \atop {x^{2} + y^{2} -2xy=9}} \right. \\\\\\\left \{ {{y=-2x-12} \atop {(x-y)^{2} =9}} \right. \\\\\\\left \{ {{y=-2x-12} \atop {\left[\begin{array}{ccc}x-y=-3\\x-y=3\end{array}\right }} \right. \\\\\\1)\\\\\left \{ {{x-y=-3} \atop {y=-2x-12}} \right. \\\\\\\left \{ {{x-(-2x-12)=-3} \atop {y=-2x-12}} \right. \\\\\\\left \{ {{x+2x+12=-3} \atop {y=-2x-12}} \right. \\\\\\\left \{ {{3x=-15} \atop {y=-2x-12}} \right.

\displaystyle\bf\\\left \{ {{x=-5} \atop {y=-2\cdot (-5)-12}} \right.\\\\\\\left \{ {{x=-5} \atop {y=10-12}} \right. \\\\\\\left \{ {{x_{1} =-5} \atop {y_{1} =-2}} \right. \\\\2)\\\\\left \{ {{x-y=3} \atop {y=-2x-12}} \right. \\\\\\\left \{ {{x-(-2x-12)=3} \atop {y=-2x-12}} \right. \\\\\\\left \{ {{x+2x+12=3} \atop {y=-2x-12}} \right. \\\\\\\left \{ {{3x=-9} \atop {y=-2x-12}} \right. \\\\\\\left \{ {{x=-3} \atop {y=-2\cdot(-3)-12}} \right. \\\\\\\left \{ {{x=-3} \atop {y=6-12}} \right.

\displaystyle\bf\\\left \{ {{x_{2} =-3} \atop {y_{2} =-6}} \right. \\\\\\Otvet \ : \ (-5 \ ; \ -2) \ , \ (-3 \ ; \ -6)

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