a: \(\left(\dfrac{1}{5}\right)\cdot\left(\dfrac{1}{5}\right)^{15}=\left(\dfrac{1}{5}\right)^{1+15}=\left(\dfrac{1}{5}\right)^{16}\)

b: \(\left(-10,2\right)^{10}:\left(-10,2\right)^3=\left(-10,2\right)^{10-3}=\left(-10,2\right)^7\)

c: \(\left[\left(-\dfrac{7}{9}\right)^7\right]^8=\left(-\dfrac{7}{9}\right)^{7\cdot8}=\left(-\dfrac{7}{9}\right)^{56}\)

254 . 28 = 58 . 28 = 108

giúp mik với

158 . 94 = 158 . 38 = 458

108 : 28 = (10:2)8 = 58

272 : 253 = (33)2 : (52)3 

= 33.2 : 52.3

 = 36 :  5 6 = 3 5 6

\(0,125^3.512\)

=\(\left(\dfrac{1}{8}\right)^3.8^3\)

= \(\dfrac{1}{8^3}.8^3\)

=\(6^3\)

  (0,125)³. 512

=  (0,125)³. 8³

= (0,125.8)³

= 1³

= \(\left(\dfrac{1}{1^{ }}\right)^3\)

D.2¹

^{Vì (-120) :(-60)=2}

^{Mà 2=2^1}

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

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

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

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