-15x^2 + 2x + 1 = (-5x - 1)(3x - 1-16x^2 + 8x + 3 = (-4x - 3)(4x - 1-12x^2 + 7x - 12 = (-4x + 3)(3x - 4-7x^2 - 6x - 1 = (7x + 1)(-x - 1)
-15x^2 + 2x + 1 = (-5x - 1)(3x - 1
-16x^2 + 8x + 3 = (-4x - 3)(4x - 1
-12x^2 + 7x - 12 = (-4x + 3)(3x - 4
-7x^2 - 6x - 1 = (7x + 1)(-x - 1)