\(125^7-25^{10}+5^{19}\)
\(=\left(5^3\right)^7-\left(5^2\right)^{10}+5^{19}\)
\(=5^{21}-5^{20}+5^{19}\)
\(=5^{19}.\left(5^2-5+1\right)\)
\(=5^{19}.21\)
\(=5^{18}.5.21\)
\(=5^{18}.105\)
Ta có: \(105⋮105\)
\(\Rightarrow5^{18}.105⋮105\)
\(\Rightarrow125^7-25^{10}+5^{19}⋮105\)
đpcm
\(125^7-25^{10}+5^{19}\)
\(=\left(5^3\right)^7-\left(5^2\right)^{10}+5^{19}\)
\(=5^{21}-5^{20}+5^{19}\)
\(=5^{19}.\left(5^2-5+1\right)\)
\(=5^{19}.21\)
\(=5^{18}.5.21=5^{18}.105⋮105\)
Vậy ......
hai bạn trả lời ai cũng là ctv hết nhỉ? thật giỏi ha
