\(a.\)
Ta có : \(x=100^{30}=\left(100^3\right)^{10}=1000000^{10}\)
\(y=2^{100}=\left(2^{10}\right)^{10}=1024^{10}\)
Vì \(1000000^{10}>1024^{10}\Rightarrow x>y\)
\(b.\)
Ta có : \(a=3^{450}=\left(3^3\right)^{150}=27^{150}\)
\(b=5^{300}=\left(5^2\right)^{150}=25^{150}\)
Vì \(27^{150}>25^{150}\Rightarrow a>b\)