B=(3+1).(3^2+1).(3^4+1).(3^8+1).(3^16 +1).2
=>B=2.(3+1)(32+1)(34+1)(38+1).(316+1)
=(3-1)(3+1)(32+1)(34+1)(38+1).(316+1)
=(32-1)(32+1)(34+1)(38+1).(316+1)
=(34-1)(34+1)(38+1).(316+1)
=(38-1)(38+1).(316+1)
=(316-1)(316+1)
=332-1=A
Vậy A=B
\(B=2.\left(3+1\right)\left(3^2+1\right)\left(3^4+1\right)\left(3^8+1\right).\left(3^{16}+1\right)\)
\(=\left(3-1\right).\left(3+1\right).\left(3^2+1\right).\left(3^4+1\right).\left(3^8+1\right).\left(3^{16}+1\right)\)
\(=\left(3^2-1\right).\left(3^2+1\right).\left(3^4+1\right).\left(3^8+1\right).\left(3^{16}+1\right)\)
\(=\left(3^4-1\right).\left(3^4+1\right).\left(3^8+1\right).\left(3^{16}+1\right)\)
\(=\left(3^8-1\right).\left(3^8+1\right).\left(3^{16}+1\right)\)
\(=\left(3^{16}-1\right).\left(3^{16}+1\right)\)
\(=3^{32}-1\)
Vậy A = B = 332 - 1
ta có A=332-1=(316+1)(316-1)=(316+1)(38+1)(38-1)=(316+1)(38+1)(34+1)(34-1)
=(316+1)(38+1)(34+1)(32+1)(32-1)=(316+1)(38+1)(34+1)(32+1)(3+1)(3-1)=B
=> A=B