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

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

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

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

Số hữu tỉ \(\frac{8}{625}\) được viết dưới dạng lũy thừa là :

\(\frac{8}{625}=\frac{2^3}{5^4}\)

\(\frac{8}{625}=\frac{2^3}{25^2}\)

\(\frac{8}{625}=\frac{2^3}{25^2}\)

\(\frac{8}{625}=\frac{2^3}{5^4}\)

Cách viết:

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

chúc bạn vui vẻ

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

.

Bài 1:

\(\left(\frac{1}{2}\right)^{2n-1}=\frac{1}{8}\\ \left(\frac{1}{2}\right)^{2n-1}=\left(\frac{1}{2}\right)^3\\ 2n-1=3\\ 2n=3+1\\ 2n=4\\ n=4:2\\ n=2\)

Bài 2:

\(\frac{81}{625}=\left(\frac{3}{5}\right)^4=\left(\frac{9}{25}\right)^2\)

(9/25)² nhé

\(\dfrac{81}{625}=\left(\dfrac{3}{5}\right)^4=\left(-\dfrac{3}{5}\right)^4=\left(\dfrac{9}{25}\right)^2=\left(-\dfrac{9}{25}\right)^2\)

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

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

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

(ko bt là đủ chưa nữa)