Question

решите систему уравнений способом сложения

Answer 1

$3x + 9y = - 5 \\ x + 5y = 6 \: \: | \times ( - 3) \\ \\ 3x + 9y = - 5 \\ - 3x - 15y = - 18 \\ \\ - 6y = - 23 \\ y = - 23 \div ( - 6) \\ y = 3 \frac{5}{6} \\ \\ x + 5y = 6 \\ x + 5 \times 3 \frac{5}{6} = 6 \\ x = 6 - 5 \times \frac{23}{6} \\ x = 6 - 19 \frac{1}{6} \\ x = - 13 \frac{1}{6} \\ \\ otvet: \: \: ( - 13 \frac{1}{6} \: ; \: 3 \frac{5}{6} )$