Ответ: x₁ = - 3/7; x₂ = -5.

Объяснение:

у = 7x² + 38x + 14

у = - 1

- 1 = 7x² + 38x + 14

7x² + 38x + 14 + 1 = 0

7x² + 38x + 15 = 0

7x² + 35x + 3x + 15 = 0

7x(x + 5) + 3(x + 5) = 0

(7x + 3)(x + 5) = 0

1) 7x + 3 = 0

  7x = -3

  x = - 3/7

2) x + 5 = 0

   x = - 5