Ta có: \(7^{64}-48\left(7^2+1\right)\left(7^4+1\right)\left(7^8+1\right)\left(7^{16}+1\right)\left(7^{32}+1\right)\)
\(=7^{64}-\left(7^2-1\right)\left(7^2+1\right)\left(7^4+1\right)\left(7^8+1\right)\left(7^{16}+1\right)\left(7^{32}+1\right)\)
\(=7^{64}-\left(7^4-1\right)\left(7^4+1\right)\left(7^8+1\right)\left(7^{16}+1\right)\left(7^{32}+1\right)\)
\(=7^{64}-\left(7^{64}-1\right)\)
\(=7^{64}-7^{64}+1\)
\(=1.\)
bài này thi violympic à Nguyễn Thị Uyển Nhi