Ta có: 87 - 218 = (23)7 - 218 = 221 – 218 = 217.( 24 -2)= 217.(16 - 2) = 24.14 ⋮ 14

Ta có :

8⁷ - 2¹⁸ = ( 2³ )⁷ - 2¹⁸= 2²¹ -  2¹⁸ = 2¹⁸ ( 2³ - 1 ) = 2¹⁸ . 7 = 2¹⁷ .2.7 = 2¹⁷ . 14 ( chia hết cho 14 )

Vậy 8⁷-2¹⁸chia hết cho 14

Tao không biết và tao cũng chẳng quan tâm

ko biết

Bài 1:Ta có:3¹⁵+3¹⁴=3¹⁴.3+3¹⁴=3¹⁴.4 chia hết cho 4

Bài 2:a,\(3A=3+3^2+3^3+...........+3^{2016}\)

\(\Rightarrow3A-A=\left(3+3^2+.......+3^{2016}\right)-\left(1+3+.......+3^{2015}\right)\)

\(\Rightarrow2A=3^{2016}-1\Rightarrow A=\frac{3^{2016}-1}{2}\)

b,Ta có:A=1+3+3²+3³+.............+3²⁰¹⁵

=(1+3)+(3²+3³)+...............+(3²⁰¹⁴+3²⁰¹⁵)

=4+3².4+................+3²⁰¹⁴.4

=4.(1+3²+.........+3²⁰¹⁴) chia hết cho 4

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