Question

помогите мне пожалуйста​

Answer 1

Ответ:

(4,2; 5,6)

Объяснение:

x = -7 + 2y

Подставляем значение:

7(-7 + 2y) - 4y = 7

-49 + 14y - 4y = 7

10y = 7 + 49 = 56

y = 56/10 = 5,6

x = -7 + 2×5,6 = 11,2 - 7 = 4,2

Answer 2

$\left \{ {{x-2y=-7} \atop {7x-4y=7}} \right.\\\\\left \{ {{x=2y-7} \atop {7*(2y-7)-4y=7}} \right.\\\\\left \{ {{x=2y-7} \atop {14y-49-4y=7}} \right.\\\\\left \{ {{x=2y-7} \atop {10y=56}} \right. \\\\\left \{ {{x=2*5,6-7} \atop {y=5,6}} \right.\\\\\left \{ {{x=11,2-7} \atop {y=5,6}} \right.\\\\\left \{ {{x=4,2} \atop {y=5,6}} \right. \\\\Otvet:\boxed{(4,2 \ ; \ 5,6)}$