Câu hỏi của Nguyễn Minh Thi

Question

2) tìm số tự nhiên n biết:

$\left(\dfrac{1}{3}\right)^n=\dfrac{1}{27};\left(\dfrac{3}{5}\right)^n=\dfrac{81}{625}$

Mashiro Shiina · Accepted Answer

$\left(\dfrac{1}{3}\right)^n=\left(\dfrac{1}{27}\right)$

$\Rightarrow\left(\dfrac{1}{3}\right)^n=\left(\dfrac{1}{3}\right)^3$

$\Rightarrow n=3$

$\left(\dfrac{3}{5}\right)^n=\dfrac{81}{625}$

$\Rightarrow\left(\dfrac{3}{5}\right)^n=\left(\dfrac{3}{5}\right)^4$

$\Rightarrow n=4$Câu trả lời: $\left(\dfrac{1}{3}\right)^n=\left(\dfrac{1}{27}\right)$

$\Rightarrow\left(\dfrac{1}{3}\right)^n=\left(\dfrac{1}{3}\right)^3$

$\Rightarrow n=3$

$\left(\dfrac{3}{5}\right)^n=\dfrac{81}{625}$

$\Rightarrow\left(\dfrac{3}{5}\right)^n=\left(\dfrac{3}{5}\right)^4$

$\Rightarrow n=4$

Đức Hiếu · Answer

a, $\left(\dfrac{1}{3}\right)^n=\dfrac{1}{27}\Rightarrow\left(\dfrac{1}{3}\right)^n=\left(\dfrac{1}{3}\right)^3$

Vì $\dfrac{1}{3}\ne-1,\dfrac{1}{3}\ne0;\dfrac{1}{3}\ne1$ nên $n=3$

Vậy........

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

Vì $\dfrac{3}{5}\ne-1,\dfrac{3}{5}\ne0;\dfrac{3}{5}\ne1$ nên $n=4$

Vậy..........

Chúc bạn học tốt!!!Câu trả lời: a, $\left(\dfrac{1}{3}\right)^n=\dfrac{1}{27}\Rightarrow\left(\dfrac{1}{3}\right)^n=\left(\dfrac{1}{3}\right)^3$

Vì $\dfrac{1}{3}\ne-1,\dfrac{1}{3}\ne0;\dfrac{1}{3}\ne1$ nên $n=3$

Vậy........

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

Vì $\dfrac{3}{5}\ne-1,\dfrac{3}{5}\ne0;\dfrac{3}{5}\ne1$ nên $n=4$

Vậy..........

Chúc bạn học tốt!!!

lũy thừa	cơ số	cơ số	giá trị của lũy thừa
\(\left(\dfrac{4}{5}\right)^n\)	...	...	\(\left(\dfrac{4}{5}\right)^n\)=\(\dfrac{...^n}{...^n}\)
\(\left(\dfrac{...}{...}\right)^{...}\)	...	...	\(\left(\dfrac{-3}{4}\right)^n\)=\(\dfrac{\left(...\right)^n}{...^n}\)
\(\left(\dfrac{5}{-7}\right)^n\)	...	...	......

Bài 5: Lũy thừa của một số hữu tỉ