[tex]\it 4^n=(2^2)^n= (2^n)^2
\\ \\
5^{2n+1} = 5\cdot5^{2n} = 5\cdot(5^n)^2[/tex]
[tex]\it (2^n)^2\cdot5\cdot(5^n)^2 = 5\cdot(2^n)^2\cdot(5^n)^2=5\cdot(2^n\cdot5^n)^2= 5\cdot(10^n)^2[/tex]
[tex]\it 2^{2n} = (2^n)^2,\ \ \ \ 25^n = (5^2)^n= (5^n)^2[/tex]
