(3a^2 + 12a + 12) / (3a + 6)
= (3(a^2 + 4a + 4)) / (3(a + 2))
= 3(a + 2)^2 / 3(a + 2)
= (a + 2)^2 / (a + 2)
= a + 2

(8a^2 - 16a + 8) / (2a - 2)
= 8(a^2 - 2a + 1) / 2(a - 1)
= 4(2(a - 1)^2) / 2(a - 1)
= 4(2(a - 1)) = 8(a - 1)
= 8a - 8.