giúp mình câu b bài 2 ạ nhanh ạ mình đg cần gấp ạ

` # Traam `

` a ) `

` 21/47 + 9/45 + 26/47 + 4/5 `

` = 21/47 + 26/47 + 9/45 + 4/5 `

` = 47/47 + 1/5 + 4/5 `

` = 1 + 1 `

` = 2 `

_______________________

` b ) `

` ( 5^4 . 20^4 )/( 25^5 . 4^5 ) `

` = ( 5^4 . 4^4 . 5^4 )/( (5^2)^5 . 4^5 ) `

` = ( 5^4 . 5^4 . 4^4 )/( 5^2.5 . 4^5 ) `

` = ( 5^8 . 4^4 )/(5^10 . 4^5 ) `

` = 1/(5^2 . 4 ) `

` = 1/(25.4) `

` = 1/100 `