Question

Помогите решить 27. 3

Answer 1

В решении

Объяснение:

$8x {}^{2} - 2x - 1 = 8 {x}^{2} + 2x - 4x - 1 = 2x(4x + 1) - (4x + 1) = (4x + 1)(2x - 1) \\ 12x {}^{2} - x - 1 = 12 {x}^{2} + 3x - 4x - 1 = 3x(4x + 1) - (4x + 1) = (4x + 1)(3x - 1) \\- 6 {x}^{2} + x + 12 = - 6 {x}^{2} + 9x - 8 x + 12 = - 3x(2x - 3) - 4(2x - 3) = (2x - 3)( - 3x - 4) = - (3x + 4)(2x - 3) \\ - 15 {x}^{2} + 2x + 1 = - 15 {x}^{2} + 5x - 3x + 1 = - 5x(3x - 1) - (3x - 1) = (3x - 1)( - 5x - 1) = - (5x + 1)(3x - 1)$