Question

20БАЛЛОВ!

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

Answer 1

$\displaystyle\bf\\\left \{ {{x-2y=3} \atop {5x+y=4}} \right. \\\\\\\left \{ {{x=2y+3} \atop {5\cdot(2y+3)+y=4}} \right. \\\\\\\left \{ {{x=2y+3} \atop {10y+15+y=4}} \right. \\\\\\\left \{ {{x=2y+3} \atop {11y=-11}} \right. \\\\\\\left \{ {{x=2\cdot(-1)+3} \atop {y=-1}} \right. \\\\\\\left \{ {{x=1} \atop {y=-1}} \right. \\\\\\Otvet: \ \Big(1 \ ; \ -1\Big)$

Answer 2

Ответ:

x = 1

y = - 1

Объяснение:

x - 2y = 3

5x + y = 4

умножаем второе на 2 и складываем

х + 10х =3 + 8

11х =11

х=1

у = 4 - 5х = 4-5 = -1

незачто)