Simplifying
(2a + 2a2)(3 + a)

Multiply (2a + 2a2) * (3 + a)
(2a * (3 + a) + 2a2 * (3 + a))
((3 * 2a + a * 2a) + 2a2 * (3 + a))
((6a + 2a2) + 2a2 * (3 + a))
(6a + 2a2 + (3 * 2a2 + a * 2a2))
(6a + 2a2 + (6a2 + 2a3))

Combine like terms: 2a2 + 6a2 = 8a2
(6a + 8a2 + 2a3)