Question

Chứng tỏ: 4³⁹ + 4⁴⁰ + 4⁴¹ chia hết cho 28.

Giúp mình với, mình cần gấp lắm nha!!!

Answer 1

Ta có: \(4^{39}+4^{40}+4^{41}=4^{38}\left(4+4^2+4^3\right)\)

\(=4^{38}.84⋮28\left(84⋮28\right)\)

\(\Rightarrow4^{39}+4^{40}+4^{41}⋮28\left(đpcm\right)\)

Answer 2

\(4^{39}+4^{40}+4^{41}\)

\(=4^{38}.\left(4+4^2+4^3\right)\)

\(=4^{38}.84\)

\(\Rightarrow4^{38}+4^{40}+4^{41}⋮28\)

\(\Rightarrowđpcm\)

Answer 3

4\(^{39}\) + 4\(^{40}\) + 4\(^{41}\) chia hết cho 28

ta có : 4\(^{39}\)+4\(^{40}\)=4\(^{38}\)(4+4\(^2\)+4\(^3\))

=4\(^{38}\).84\(⋮\)(84\(⋮\)28)

=4\(^{39}\)+\(^{40}\)+4\(^{41}\)\(⋮\)28

=đpcm