`B =2^100 - 2^99 - 2^98 - ... -2^2 -2`
`=> B = -(2 +2^2 + ... +2^98 +2^99 + 2^100 )`
Đặt `A =2 +2^2 + ... +2^98 +2^99 + 2^100 -> B = -A`
`=>2A = 2^2 +2^3 +.... +2^99 +2^100 +2^101`
`=> 2A - A = ( 2^2 +2^3 +.... +2^99 +2^100 +2^101) -(2 +2^2 + ... +2^98 +2^99 + 2^100 )`
`=> A = 2^101 - 2`
`=> B = -A = -(2^201-2) = 2 -2^201`
Vậy `B= 2 -2^201` .