(a + 6)³ - 27 = (a + 6)³ - 3³ = (a + 6 - 3)((a + 6)² + 3 * ( a + 6) + 3²) =
= (a + 3)(a² + 12a + 36 + 3a + 18 + 9) = (a + 3)(a² + 15a + 63)
(2x - 1)³ + 64 = (2x - 1)³ + 4 ³ = (2x - 1 + 4)((2x - 1)² + 4 * (2x - 1) + 4 ²) =
= (2x + 3)(4x² - 4x + 1 + 8x - 4 + 16) = ( 2x + 3)(4x² + 4x + 13)