2.4 1) (a+ 3)3 =a3+ 3a2·3 + 3a·32+ 33 =a3+ 9a2+ 27a+ 27 2) (a−2)3 =a3−3a2·2 + 3a·22−23 =a3−6a2+ 12a−8 3) (x+ 1)3 =x3+ 3x2·1 + 3x·12+ 13 =x3 + 3x2+ 3x+ 1 4) (2−a)3 = 23 −3·22·a+ 3·2·a2 −a3 = 8−12a+ 6a2−a3 5) (a+ 2)3 =a3+ 3a2·2 + 3a·22+ 23 =a3+ 6a2+ 12a+ 8 6) (a−1)3 =a3−3a2·1 + 3a·12−13 =a3−3a2+ 3a−1
7) (2x−1)3 = (2x)3 −3·(2x)2·1 + 3·2x·12−13 = 8x3−12x2+ 6x−1 8) (a2 −1)3 = (a2)3−3 (a2)2 ·1 + 3a2·12−13 =a6 −3a4+ 3a2−1
9) (a2 +b3)3 = (a2)3+ 3 (a2)2b3+ 3a2(b3)2+ (b3)3 =a6+ 3a4b3+ 3a2b6+b9
Algèbre : factorisation Corrigé 2.4