Question

[Pham Trong Bach]

Tính nhanh:

a) 101 3 ;                                             b) 47 3   +   9 . 47 2  + 27.47 + 27;

c) 299 3 ;                                             d) 1008 3   –   3 . 1008 2 . 8   +   3 . 1008 . 8 2   –   2 6 .

Answer 1

[Cao Minh Tâm]

a) ( 100   +   1 ) 3   =   100 3   +   3 . 100 2 + 3.100 + 1 = 1030301.

b) ( 47   +   3 ) 3   =   50 3  = 125000.

c) ( 300   –   1 ) 3  = 26730899.

d) ( 1008   –   23 ) 3   =   1000 3   =   10 9 .