Simplifying
2(3(4 + p) + p) + p
2((4 * 3 + p * 3) + p) + p
2((12 + 3p) + p) + p

Combine like terms: 3p + p = 4p
2(12 + 4p) + p
(12 * 2 + 4p * 2) + p
(24 + 8p) + p

Combine like terms: 8p + p = 9p
24 + 9p