Giải:
\(A=2^{100}-2^{99}-2^{98}-...-2^2-2^1.\)
\(\Rightarrow2A=2\left(2^{100}-2^{99}-2^{98}-...-2^2-2^1\right).\)
\(\Rightarrow2A=2^{101}-2^{100}-2^{99}-...-2^3-2^2.\)
\(\Rightarrow2A-A=\left(2^{101}-2^{100}-2^{99}-...-2^3-2^2\right)-\left(2^{100}-2^{99}-2^{98}-...-2^2-2^1\right).\)
\(\Rightarrow A=2^{101}-2.\)
Vậy.....