Question

решите систему уравнений способом подстановки
3y+6x=5 4x-y=15​

Answer 1

$3y + 6x = 5 \\ 4x - y = 15 \\ \\3(4x - 15) + 6x = 5 \\ y = 4x - 15 \\ \\ 3(4x - 15) + 6x = 5 \\ 12x - 45 + 6x = 5 \\ 18x = 5 + 45 \\ 18x = 50 \\ x = \frac{50}{18} \\ x = \frac{25}{9} \\ x = 2 \frac{7}{9} \\ \\ y = 4x - 15 = \frac{4 \times 25}{9} - 15 = \frac{100}{9} - 15 = 11 \frac{1}{9} - 15 = - 3 \frac{8}{9} \\ \\ Ответ:(2 \frac{7}{9} \: ; \: - 3 \frac{8}{9} )$