Question

(2+1)(2²+1)(2⁴+1)(2⁸+1)(2¹⁶+1)(2³²+1)

Answer 1

Nhân với 2-1 áp dụng bất đẳng thức a^2-b^2=(a-b)(a+b)

=> 2^64-1

Answer 2

(2+1)(2²+1)(2⁴+1)(2⁸+1)(2¹⁶+1)(2³²+1)

=[3(2²+1)(2⁴+1)](2⁸+1)(2¹⁶+1)(2³²+1)

=[(2²-1)(2²+1)](2⁴+1)(2⁸+1)(2¹⁶+1)(2³²+1)

=[(2⁴-1)(2⁴+1)](2⁸+1)(2¹⁶+1)(2³²+1)

=[(2⁸-1)(2⁸+1)](2¹⁶+1)(2³²+1)

=[(2¹⁶-1)(2¹⁶+1)](2³²+1)

=(2³²-1)(2³²+1)