\(2^{300}+3^{300}+4^{300}-729.24^{100}=\)
\(=2^{300}+3^{300}+\left(2^2\right)^{300}-3^6.\left(2^3.3\right)^{100}=\)
\(=2^{300}+3^{300}+2^{600}-2^{300}.3^{106}=\)
\(=2^{300}\left(1+2^{300}-3^{106}\right)+3^{300}\)
Ta có
\(2^{300}=\left(2^2\right)^{150}=4^{150}>3^{150}>3^{106}\Rightarrow2^{300}-3^{106}>0\)
\(\Rightarrow2^{300}\left(1+2^{300}-3^{106}\right)+3^{300}>0\)
\(\Rightarrow2^{300}+3^{300}+4^{300}>729.24^{100}\)