1)
16 - 9а² - 72ab - 144b² =
= - ( (3a)² + 2*3a*12b + (12b)² - 4² )=
= - ( (3a + 12b)² - 4² ) =
= - (3a + 12b - 4)(3a + 12b + 4)
2)
ac³+c³ - 27a - 27 =
= c³(a + 1) - 27(a + 1) =
= (a + 1)(c³ - 27) =
= (a + 1)(c³ - 3³ ) =
= (a + 1)(c - 3)(c² + 3c + 3²) =
= (a + 1)(c - 3)(c² + 3c + 9)
3)
32 + 243a⁵ = (3a)⁵ + 2⁵ =
= (3a + 2)( (3a)⁴ - (3a)³ * 2 + (3a)² * 2² - 3a * 2³ + 2⁴ )
= (3a + 2)( 81a⁴ - 27a³ * 2 + 9a²* 4 - 3a * 8 + 16)
= (3a + 2)(81a⁴ - 54a³ + 36a² - 24a + 16 )