Question

система уравнений 3x + 9y = -5 x +5y = -3

Answer 1

3x + 9y = -5
x + 5y = -3

x = -3 - 5y
3(-3 - 5y) + 9y = -5

x = -3 - 5y
-9 - 15y + 9y = -5

x = -3 - 5y
-6y = 4

x = -3 - 5y
y = -2/3

y = -2/3
x = -3 + 10/3

y = -2/3
x = -1/3 

Ответ: (-1/3; -2/3).