B = 1 + 2 + 3 + ... + 98 + 99

\(=\frac{99.\left(99+1\right)}{2}\)

=9900/2

=4950

M=(7^0+7^1)+(7^2+7^3)+....+(7^68+7^69)

M=8+7^2(1+7)+...+7^68.(1+7)

M=8+7^2.8+...+7^68.8

8.(1+7^2+...+7^68) Chia hết cho 4

tick cho mình nhé đúng rồi đấy

\(\left\{{}\begin{matrix}99^{29}=\left(99^2\right)^{10}=9801^{10}\\9999^{10}=9999^{10}\end{matrix}\right.\)

\(9801^{10}< 9999^{10}\Leftrightarrow99^{20}< 9999^{10}\)

\(\left\{{}\begin{matrix}\left|-\dfrac{25}{46}\right|=\dfrac{25}{46}>0\\\left(-\dfrac{25}{46}\right)^{2005}< 0\end{matrix}\right.\)

\(\Rightarrow\left(-\dfrac{25}{46}\right)^{2005}< \left|-\dfrac{25}{46}\right|\)