[tex]a) \\ \\
7 \sqrt{2} \sim 3 \sqrt{11} \\ \\
(7 \sqrt{2})^2 \sim (3 \sqrt{11})^2 \\ \\
49 \times 2\sim 9 \times 11 \\ \\
98 \ \textless \ 99 \\ \\
\Longrightarrow~~\boxed{7 \sqrt{2} \ \textless \ 3 \sqrt{11}} \\ \\ \\
b) \\ \\
2^{300} \sim 3^{200} \\ \\
2^{3\times 100} \sim 3^{2 \times 100} \\ \\
\Big(2^3\Big)^{100} \sim \Big(3^2\Big)^{100} \\ \\
8^{100} \ \textless \ 9^{100} \\ \\
\Longrightarrow~~\boxed{2^{300} \ \textless \ 3^{200} }[/tex]