Предмет: Алгебра, автор: olegshkoldin3009

Даю 60 баллов. 1.23 (3 и 4) пжж

Приложения:

Ответы

Автор ответа: world72

Ответ:

3. (-2;1) 4. (1, 2)

Объяснение:

$\left \{ {{5x-2y=-12} \atop {3x+4y=-2}} \right. \\$

Умножим первое уравнение на 2 и сложим первое и второе.

$\left \{ {{10x-4y=-24} \atop {3x+4y=-2}} \right.$

$13x=-26\\x = -2$

Подставим полученный х в любое из уравнений и найдем у.

$3*(-2)+4y=-2\\-6+4y=-2\\4y=4\\y=1$

$\left \{ {{x+2y=5} \atop {-x+7y=13}} \right.$

Сложим первое со вторым.

$9y=18\\y = 2\\$

Подставим полученный y в любое из уравнений и найдем x.

$x+2*2=5\\x = 5-4\\x=1$

olegshkoldin3009: Спасибо

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