a) Ta có:
\(A=\left(2+1\right)\left(2+1\right)\left(2+1\right)\left(2+1\right)\left(2+1\right)\)
\(A=3.3.3.3.3\)
\(A=3^5\)
\(A=243\)
Ta lại có:
\(B=2^{32}\)
\(B=2^8.2^{24}\)
\(B=256.2^{24}\)
=> Dễ dàng thấy được A < B
b) \(C=\left(3+1\right)\left(3^2+1\right)\left(3^4+1\right)\left(3^8+1\right)\left(3^{16}+1\right)\)
\(C=\dfrac{1}{2}\left(3-1\right)\left(3+1\right)\left(3^2+1\right)\left(3^4+1\right)\left(3^8+1\right)\left(3^{16}+1\right)\)
\(C=\dfrac{1}{2}\left(3^2-1\right)\left(3^2+1\right)\left(3^4+1\right)\left(3^8+1\right)\left(3^{16}+1\right)\)
\(C=\dfrac{1}{2}\left(3^4-1\right)\left(3^4+1\right)\left(3^8+1\right)\left(3^{16}+1\right)\)
\(C=\dfrac{1}{2}\left(3^8-1\right)\left(3^8+1\right)\left(3^{16}+1\right)\)
\(C=\dfrac{1}{2}\left(3^{16}-1\right)\left(3^{16}+1\right)\)
\(C=\dfrac{1}{2}\left(3^{32}-1\right)\)
=> C < D
