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20 tháng 9 2016

a ) \(\left(\frac{1}{3}\right)^m=\left(\frac{1}{3}\right)^4\)

\(\Rightarrow m=4\)

b ) \(\left(\frac{3}{5}\right)^n=\left(\frac{9}{25}\right)^5\)

       \(\Leftrightarrow\left(\frac{3}{5}^2\right)^n=\left(\frac{9}{25}\right)^5\)

       \(\Leftrightarrow\left(\frac{9}{25}\right)^n=\left(\frac{9}{25}\right)^5\)

       \(\Leftrightarrow n=5\)

c ) \(\left(-0,25\right)^p=\frac{1}{256}\)

   \(\Leftrightarrow\left(-\frac{1}{4}\right)^p=\frac{1}{256}\)

   \(\Leftrightarrow\left(-\frac{1}{4}\right)^p=\left(-\frac{1}{4}\right)^4\)

   \(\Leftrightarrow p=4\)

25 tháng 9 2016

 

\(a.\)

\(\left(\frac{1}{3}\right)^m=\frac{1}{81}\)

\(\Rightarrow\left(\frac{1}{3}\right)^m=\left(\frac{1}{3}\right)^4\)

\(\Rightarrow m=4\)

Vậy :        \(m=4\)

\(b.\)

\(\left(\frac{3}{5}\right)^n=\left(\frac{9}{25}\right)^5\)

\(\Rightarrow\left(\frac{3}{5}\right)^n=\left(\frac{3}{5}\right)^{15}\)

\(\Rightarrow n=5\)

Vậy :        \(n=5\)

\(c.\)

\(\left(-0,25\right)^p=\frac{1}{256}\)

\(\Rightarrow\left(-\frac{1}{4}\right)^p=\frac{1}{256}\)

\(\Rightarrow\left(-\frac{1}{4}\right)^p=\left(\frac{1}{4}\right)^4\)

\(\Rightarrow p=4\)

Vậy :        \(p=4\)

 

13 tháng 9 2017

a/ \(\left(\frac{1}{3}\right)^m=\frac{1}{81}\)

\(\Leftrightarrow\left(\frac{1}{3}\right)^m=\left(\frac{1}{3}\right)^4\)

\(\Leftrightarrow m=4\left(tm\right)\)

b/ \(\left(\frac{3}{5}\right)^n=\left(\frac{9}{25}\right)^5\)

\(\Leftrightarrow n=10\)

\(\Leftrightarrow\left(\frac{3}{5}\right)^n=\left(\frac{3}{5}\right)^{10}\)

13 tháng 9 2017

a)(1/3)^m=(1/3)^4

b)(3/5)^n=(3/5)^10

c)(-0,25)^p=(-0,25)^4

10 tháng 9 2017

a) \(\left(\dfrac{1}{3}\right)^m=\dfrac{1}{81}\)

\(\Rightarrow\dfrac{1^m}{3^m}=\dfrac{1}{81}\)

\(\Rightarrow\dfrac{1}{3^m}=\dfrac{1}{3^4}\)

\(\Rightarrow m=4\)

b) \(\left(\dfrac{3}{5}\right)^n=\left(\dfrac{9}{25}\right)^5\)

\(\Rightarrow\left(\dfrac{3}{5}\right)^n=\left[\left(\dfrac{3}{5}\right)^2\right]^5\)

\(\Rightarrow\left(\dfrac{3}{5}\right)^n=\left(\dfrac{3}{5}\right)^{10}\)

\(\Rightarrow n=10\)

c) \(\left(-0,25\right)^p=\dfrac{1}{256}\)

\(\Rightarrow\left(\dfrac{-1}{4}\right)^p=\dfrac{1}{256}\)

\(\Rightarrow\left(\dfrac{-1}{4}\right)^p=\dfrac{1}{4^4}\)

\(\Rightarrow\left(\dfrac{-1}{4}\right)^p=\left(\dfrac{1}{4}\right)^4\)

\(\Rightarrow p=4\)

HQ
Hà Quang Minh
Giáo viên
16 tháng 9 2023

a)

 \(\begin{array}{l}\left( {0,25 - \frac{5}{6}} \right).1,6 + \frac{{ - 1}}{3}\\ =(\frac{25}{100}-\frac{5}{6}).\frac{16}{10}+\frac{-1}{3}\\= \left( {\frac{1}{4} - \frac{5}{6}} \right).\frac{8}{5} + \frac{{ - 1}}{3}\\ = \left( {\frac{6}{{24}} - \frac{{20}}{{24}}} \right).\frac{8}{5} + \frac{{ - 1}}{3}\\ = \frac{{ - 14}}{{24}}.\frac{8}{5} + \frac{{ - 1}}{3}\\ = \frac{{ - 14}}{{15}} + \frac{{ - 1}}{3}\\ = \frac{{ - 14}}{{15}} + \frac{{ - 5}}{{15}}\\ = \frac{{ - 19}}{{15}}\end{array}\)

b)

\(\begin{array}{l}3 - 2.\left[ {0,5 + \left( {0,25 - \frac{1}{6}} \right)} \right]\\ = 3 - 2.\left[ {\frac{1}{2} + \left( {\frac{1}{4} - \frac{1}{6}} \right)} \right]\\ = 3 - 2.\left( {\frac{1}{2} + \frac{1}{{12}}} \right)\\ =3-2.(\frac{6}{12}+\frac{1}{12})\\= 3 - 2.\frac{7}{{12}}\\ = 3 - \frac{7}{6}\\=\frac{18}{6}-\frac{7}{6}\\ = \frac{{11}}{6}\end{array}\)

  
1 tháng 4 2018

A​=0,125 • 4 • 16/9•4/5•27/8=12/5

1 tháng 4 2018

\(A=\left(0,25\right)^{-1}.\left(\frac{1}{4}\right)^{-2}.\left(\frac{4}{3}\right)^2.\left(\frac{5}{4}\right)^{-1}.\left(\frac{2}{3}\right)^{-3}\)

\(\Rightarrow A=4^1.4^2.\frac{16}{9}.\frac{4}{5}\frac{27}{8}\)

\(\Rightarrow A=\frac{64}{1}.\frac{16}{9}.\frac{4}{5}.\frac{27}{8}\)

\(\Rightarrow A=\frac{1536}{5}\)

Vậy \(A=\frac{1536}{5}\)

8 tháng 9 2016

Câu 1:

a)\(\frac{3}{4}-0,25-\left[\frac{7}{3}+\left(-\frac{9}{2}\right)\right]-\frac{5}{6}\)

    \(=\frac{3}{4}-\frac{1}{4}-\frac{14}{6}+\frac{27}{6}-\frac{5}{6}\)

    \(=\frac{1}{2}-\frac{4}{3}\)

     \(=-\frac{5}{6}\)

b)\(7+\left(\frac{7}{12}-\frac{1}{2}+3\right)-\left(\frac{1}{12}+5\right)\)

    \(=7+\frac{1}{12}+3-\frac{1}{12}-5\)

    \(=5\)

8 tháng 9 2016

Câu 2:

\(\frac{3}{4}-\frac{5}{6}\le\frac{x}{12}< 1-\left(\frac{2}{3}-\frac{1}{4}\right)\)

\(-\frac{1}{12}\le\frac{x}{12}< 1-\frac{5}{12}\)

\(-\frac{1}{12}\le\frac{x}{12}< \frac{7}{12}\)

           Vậy -1\(\le\)x<7

23 tháng 5 2017

Ta có \(0,25=\dfrac{1}{4}\) nên \(\left(0,25\right)^n=\left(\dfrac{1}{4}\right)^n\)\(256=4^4\) nên \(\dfrac{1}{256}=\dfrac{1}{4^4}=\left(\dfrac{1}{4}\right)^4\)

Vậy: \(\left(\dfrac{1}{4}\right)^n=\left(\dfrac{1}{4}\right)^4,\) từ đó n = 4