Cho A = 2 + 2^2 + 2^3 + ... + 2^100, Cho a = 2 + 2^2 + 2^3 + ... +2^100, Cho A = 2 + 2^2 + 2^3 +...+ 2^100, Cho a = 2 + 2^2 + 2^3 +...+ 2^100, Cho a=2+2^2+2^3+..2^100