Đáp án + Giải thích các bước giải:
`B=3(2^2+1)(2^4+1)(2^8+1)...(2^64+1)+1`
`=(2^2-1)(2^2+1)(2^4+1)(2^8+1)....(2^64+1)+1`
`=(2^4-1)(2^4+1)(2^8+1)....(2^64+1)+1`
`=(2^8-1)(2^8+1)....(2^64+1)+1`
`=(2^16-1)(2^16+1)(2^32+1)(2^64+1)+1`
`=(2^32-1)(2^32+1)(2^64+1)+1`
`=(2^64-1)(2^64+1)+1=2^128-1+1=2^128`
@RX