Ta có : M = 1+2+22+23+...+250
=> 2M = 2+22+23+...+251
=> 2M - M = 251 - 1
=> M = 251 - 1
Mà N = 251 => M < N
Ta có
M = 1 + 2 + 22 + ... + 250
2M = 2 + 22 + 23 + ... + 251
2M - M = (2 + 22 + 23 + ... + 251) - (1 + 2 + 22 + ... + 250)
M = 251 - 1
Vì 251 - 1 < 251 nên M < N
Vậy M < N
Ủng hộ mk nha !!! ^_^
\(M=1+2+2^2+2^3+...+2^{50}\)
\(\Rightarrow2M=2\left(1+2+2^2+2^3+.....+2^{50}\right)=2+2^2+2^3+.....+2^{51}\)
\(\Rightarrow M=2M-M=\left(2+2^2+2^3+....+2^{51}\right)-\left(1+2+2^2+.....+2^{50}\right)\)
\(\Rightarrow M=2^{51}-1\)
Do : \(2^{51}>2^{51}-1\)
\(\Rightarrow N>M\)