... x + + + + + ++ + + + + + + + + +( )22 2 2 2 4 4 4 4 4 4 4 4 4 4 21, (1 ) 4 (1 ) 2, 8 363, 4 4, 64 5, 64 1 6, 81 4 7, 4 81 8, 64 9, 4 10, x x x xx xx xx x yx y x x+ ++ ++ ++ ... 8 17 10 14, 3 6 4 15, 2 4 16, 2x x x x xx x x x xx x x x x xx x x + + + ++ + + + + + 23 2 3 23 2 3 23 2 4 3 212 17 217, 4 18, 3 3 219, 9 26 24 20, 2 3 3 121, 3 14 4 3 22, ... lín. Ch¼ng h¹n, víi n = 4 th× : (a + b) 4 = a 4 + 4a3b + 6a2b2 + 4ab3 + b 4 vµ víi n = 5 th× : (a + b)5 = a5 + 5a 4 b + 10a3b2 + 10a2b3 + 10ab 4 + b521. Chuyªn ®Ị...