a, 4^10 . 2^30
= ( 2^2 )^10 . 2^30
= 2^20 . 2^30
= 2^50
$$\\$$
b, 9^25 . 27^4 . 81^3
= ( 3^2 )^25 . ( 3^3 )^4 . ( 3^4 )^3
= 3^50 . 3^12 . 3^12
= 3^74
$$\\$$
c, 25^50 . 125^5
= ( 5^2 )^50 . ( 5^3 )^5
= 5^100 . 5^15
= 5^115
$$\\$$
d, 64^3 . 4^8 . 16^4
= ( 4^3 )^3 . 4^8 . ( 4^2 )^4
= 4^9 . 4^8 . 4^8
= 4^25
$$#Nhi$$
