a.\(\frac{-8}{27}=\left(\frac{-2}{3}\right)^3\)

c,\(\frac{25}{49}=\left(\frac{5}{7}\right)^2\)

1=1^2 ;125=5^3 ;-125=-5^3; 27=27^1; -27= -27^1

2: 5^2 25^1 

Cách viết:

81/625 = 3.3.3.3/5.5.5.5 = 3^4/5^4 = (3/5)^4

chúc bạn vui vẻ

\(\frac{81}{625}=\frac{9^2}{25^2}=\left(\frac{9}{25}\right)^2\)

\(\frac{81}{625}=\frac{3^4}{5^4}=\left(\frac{3}{5}\right)^4\)

`81/625 = (9^2)/(25^2) = (9/25)^2`

`81/625 = (3^4)/(5^4) = (3/5)^4`

a, \(-\dfrac{8}{27}=\left(-\dfrac{2}{3}\right)^3\)

b, \(\dfrac{81}{625}=\left(\dfrac{3}{5}\right)^4\)

c, \(27\cdot81=3^3\cdot3^4=3^7\)

d, \(\dfrac{2}{5}\cdot\dfrac{8}{125}\cdot\dfrac{16}{625}=\dfrac{2\cdot2^3\cdot2^4}{5\cdot5^3\cdot5^4}=\left(\dfrac{2}{5}\right)^8\)

a: =(-2/3)^3

b: =(3/5)^4

c: =3^3*3^4=3^7

d: =2/5*(2/5)^3*(2/5)^4=(2/5)^8

a, 10⁸ . 2⁸ = ( 2.5 )⁸ . 2⁸

                = 2⁸ . 5⁸ .2⁸

               = 2¹⁶ . 5⁸

b, 27² : 25³ = ( 3³ )² : ( 5² )³

                  = 3⁶ : 5⁶

Bài làm

a) 27² : 25³ = 

`@` `\text {Ans}`

`\downarrow`

`-1/27 = ( (-1)^3/(-3)^3) =(-1/3)^3`

`8/729 = ( (2^3)/(9^3) ) = (2/9)^3`

`16/685 = ( (4^2)/( \sqrt {685}) ) = (4/(\sqrt {685}) )^2`

a: \(2^6\cdot3^3=\left(2^2\cdot3\right)^3=12^3\)

b: \(6^4\cdot8^3=2^4\cdot3^4\cdot2^9=2^{13}\cdot3^4\)

c: \(16\cdot81=36^2\)

d: \(25^4\cdot2^8=100^4\)