Tham khảo
\(\text{+)}\)Ta có:\(5\equiv-1\left(mod3\right)\)
\(\Rightarrow5^{2022}\equiv\left(-1\right)^{2022}\left(mod3\right)\left(1\right)\)
\(\text{+)}\)Ta có:\(2\equiv-1\left(mod3\right)\)
\(\Rightarrow2^{2023}\equiv\left(-1\right)^{2023}\left(mod3\right)\left(2\right)\)
Từ \(\left(1\right)\) và \(\left(2\right)\Rightarrow5^{2022}+5^{2023}\equiv0\left(mod3\right)\)
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