Đáp án:
$B=2^{128}$
Giải thích các bước giải:
$B=3.(2^2+1).(2^4+1)....(2^{64}+1)+1$
$=(2^2-1).(2^2+1).(2^4+1)....(2^{64}+1)+1$
$=(2^4-1).(2^4+1).....(2^{64}+1)+1$
$=(2^8-1).(2^8+1)....(2^{64}+1)+1$
$=(2^{16-1})....(2^{64}+1)+1$
$=(2^{64}-1).(2^{64+1})+1$
$=2^{128}-1+1$
$=2^{128}$