Question

1+2+2^2+ ... +2^x=2^100-1

 

Answer 1

Đặt A=....

=>\(2A=2+2^2+2^3+...+2^{101}\)

\(2A-A=2^{101}-1\)

A=.....

Answer 2

Đặt A=....

=>\(2A=2+2^2+2^3+...+2^{101}\)

\(2A-A=2^{101}-1\)

A=.....

Answer 3

Đặt A=....

=>\(2A=2+2^2+2^3+...+2^{101}\)

\(2A-A=2^{101}-1\)

A=.....