Sửa đề: \(A=7^{2022}-7^{2021}+7^{2020}-7^{2019}+...+7^2-7\)
=>\(7A=7^{2023}-7^{2022}+7^{2021}-7^{2020}+...+7^3-7^2\)
=>\(8A=7^{2022}-7^{2021}+7^{2020}-7^{2019}+...+7^2-7+7^{2023}-7^{2022}+...+7^3-7^2\)
=>\(8A=7^{2023}-7\)
=>\(A=\dfrac{7^{2023}-7}{8}\)