Factorise:
(i) x2 + 14x + 49; (ii) 4x2 + 4x + 1; (iii) a2 − 10a + 25; (iv) 2x2 − 24x + 72;
(v) p2 − 24p + 144; (vi) x3 − 12x2 + 36x.