`x^3 - 9x^2 + 6x + 16`
`= x^3 - 2x^2 - 7x^2 + 14x - 8x + 16`
`= x^2(x - 2) - 7x(x - 2) - 8(x - 2)`
`= (x^2 - 7x - 8)(x - 2)`
`= (x^2 + x - 8x - 8)(x - 2)`
`= (x - 8)(x + 1)(x - 2)`
`x^3 - 6x^2 - x + 30`
`= x^3 + 2x^2 - 8x^2 - 16x + 15x + 30`
`= x^2(x + 2) - 8x(x + 2) + 15(x + 2)`
`= (x^2 - 8x + 15)(x + 2)`
`= (x^2 - 3x - 5x + 15)(x + 2)`
`= (x - 3)(x - 5)(x + 2)`
