Question

Решить систему уравнений

Answer 1

$\frac{x + 7}{3} - \frac{y - 8}{5} = 3 \\ \frac{x + 5}{4} + \frac{y + 9}{3} = 5 \\ \\ 5(x + 7) - 3(y - 8) = 45 \\ 3(x + 5) + 4(y + 9) = 60 \\ \\ 5x + 35 - 3y + 24 = 45 \\ 3x + 15 + 4y + 36 = 60 \\ \\ 5x - 3y = - 14 \\ 3x + 4y = 9 \\ \\ 20x - 12y = - 56 \\ 9x + 12y =27 \\ \\ 29x = - 29 \\ y = \frac{9 - 3x}{4} \\ \\ x = - 1 \\ y = \frac{9 - 3x}{4} \\ \\ x = - 1 \\ y = \frac{9 - 3\times ( - 1)}{4} = \frac{12}{4} = 3$
ответ: (-1; 3)