Question

Решите систему уравнений методом подстановки:

Answer 1

$7x - \frac{3y}{5} = - 4 \\ x + \frac{2y}{5} = - 3 \\ \\ x = - 3 - \frac{2y}{5} \\ 7( - 3 - \frac{2y}{5} ) - \frac{3y}{5} = - 4 \\ \\ x = - 3 - \frac{2y}{5} \\ - 21 - \frac{14y}{5} - \frac{3y}{5} = - 4 \\ \\ \\ x = - 3 - \frac{2y}{5} \\ - \frac{17y}{5} = 17 \\ \\ x = - 3 - \frac{2y}{5} \\ - 17y = 85 \\ \\ y = - 5 \\ x = - 3 - \frac{2y}{5} \\ \\ y = - 5 \\ x = - 3 - \frac{2 \times ( - 5)}{5} = - 3 + 2 = - 1$
Ответ: (-1; -5)