Ta có: 3A=32+33+...+3101
3A-A=2A=(32+33+...+3101)-(3+32+...+3100)
2A=3101-3
A=\(\frac{3^{101}-3}{2}\)
=>2A+3=2.\(\frac{3^{101}-3}{2}\)+3
=(3101-3)+3
=3101
Mà 2A+3=3n
=>3101=3n
=>n=101
A=3+32+33+...+3100
2A=(3+32+33+...+3100)x2
2A=32+33+34...+3101
2A-A=3101-3
mà 3n=2A+3=3101-3+3=3101
suy ra n=101
Ta có : A = 3 + 32 + 33 + ... + 3100
3A = 32+33+34+...+3101
Vậy 2A = 3101 - 3
Vậy 2A + 3 = 3101
=> x = 101
Ta có: 3A=32+33+...+3101
3A-A=2A=(32+33+...+3101)-(3+32+...+3100)
2A=3101-3
A=3101−323101−32
=>2A+3=2.3101−323101−32+3
=(3101-3)+3
=3101
Mà 2A+3=3n
=>3101=3n
=>n=101
