*) \(10^9+10^8-10^7\)
\(=10^6.\left(10^3+10^2+10\right)\)
\(=10^6.1110\)
Mà \(1110⋮222\) \(\Rightarrow10^6.1110⋮222\)
Vậy \(\left(10^9+10^8+10^7\right)⋮222\)
*) Sửa đề: \(8^{10}-8^9-8^8\)
\(=8^8.\left(8^2-8-1\right)\)
\(=8^8.55⋮55\)
Vậy \(\left(8^{10}-8^9-8^8\right)⋮55\)