Question

решите систему уравнений
3x+y=-1
x-xy=8

Answer 1

3x + y = - 1
x - xy = 8

y = = - 3x - 1
x - x*(- 3x - 1) = 8

x + 3x² + x - 8 = 0
3x² + 2x - 8 = 0
D = 4 + 4*3*8 = 100
x₁ = (-2 - 10)/6
x₁ = - 2
x₂ = (-2 + 10)/6
x₂ = 4/3 = 1 (1/3)
y₁ = - 3*(-2) - 1 = 5
y₂ = - 3*(4/3) - 1 = - 4 - 1 = - 5
Ответ: (-2; 5) (1(1/3); - 5)