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13 tháng 7 2016

a) \(9\cdot3^3\cdot\frac{1}{81}\cdot3^2=3^2\cdot3^3\cdot\left(\frac{1}{3}\right)^43^2=3^7\cdot\frac{1}{3^4}=3^3\)

b) \(4\cdot2^5:\left(2^3\cdot\frac{1}{16}\right)=2^2\cdot2^5:\left(2^3\cdot\frac{1}{2^4}\right)=2^7:\frac{1}{2}=2^8\)

c) \(3^2\cdot2^5\cdot\left(\frac{2}{3}\right)^2=3^2\cdot2^5\cdot\frac{2^2}{3^2}=2^7\)

d) \(\left(\frac{1}{3}\right)^2\cdot\frac{1}{3}\cdot9^2=\frac{1}{3^2}\cdot\frac{1}{3}\cdot3^4=\frac{1}{3^3}\cdot3^4=3\)

13 tháng 7 2016

a)9.33.\(\frac{1}{81}\).32

   =32.33.34.\(\frac{1}{3^4}\).32

    =311.\(\frac{1}{3^4}\)

    =37

b)4.25:(\(2^3.\frac{1}{16}\))

  =22.25:(\(2^3.\frac{1}{2^4}\))

  =27:\(\frac{2^3}{2^4}\)

  =27.\(\frac{2^4}{2^3}\)

   =\(\frac{2^{11}}{2^3}\)

   =28

c)32.25.\(\left(\frac{2}{3}\right)^2\)

   =32.25.\(\frac{2^2}{3^2}\)

   =\(\frac{3^2.2^5.2^2}{3^2}\)

   =27

d)\(\left(\frac{1}{3}\right)^2.\frac{1}{3}.9^2\)

    =\(\frac{1^2}{3^2}.\frac{1}{3}.\left(3^2\right)^2\)

    =\(\frac{1^2}{3^2}.\frac{1}{3}.3^4\)

    =\(\frac{1^2}{3^2}.\frac{3^4}{3}\)

    =\(\frac{1^2}{3^2}.3^3\)

   =3

5 tháng 7 2016

a) \(9\cdot3^3\cdot\frac{1}{81}\cdot3^2\)

\(=\frac{3^2\cdot3^3\cdot3^2}{3^4}\)

\(=3^3=27\)

b) \(4\cdot2^5:\left(2^3\cdot\frac{1}{16}\right)\)

\(=\frac{2^2\cdot2^2\cdot2^4}{2^3}\)

\(=2^5=32\)

c) \(3^2\cdot2^5\cdot\left(\frac{2}{3}\right)^2\)

\(=\frac{3^2\cdot2^5\cdot2^4}{3^2}\)

\(=2^9=512\)

d) \(\left(\frac{1}{3}\right)^2\cdot\frac{1}{3}\cdot9^2\)

\(=\frac{1^2\cdot1\cdot3^4}{3^2}\)

\(=3^2=9\)

18 tháng 6 2016

\(a,9.3^3.\frac{1}{81}.3^2=3^2.3^3.3^{\left(-4\right)}.3^2=3^{2+3-4+2}=3^3.\)

\(b,4.2^5:\left(2^3.\frac{1}{16}\right)=2^2.2^5:\left(2^3.2^{-4}\right)=2^{2+5}:2^{3-4}=2^7:2^{-1}=2^{7-\left(-1\right)}=2^8.\)

\(c,3^2.2^5.\left(\frac{2}{3}\right)^2=3^2.2^5.\frac{2^2}{3^2}=\left(\frac{3^2}{3^2}\right).\left(2^5.2^2\right)=1.2^{5+2}=2^7\)

\(d,\left(\frac{1}{3}\right)^2.\frac{1}{3}.9^2=\left(\frac{1}{3}\right)^2.\frac{1}{3}.\left(3^2\right)^2=\left(\frac{1}{3}\right)^{2+1}.3^4=\left(\frac{1}{3}\right)^3.\left(\frac{1}{3}\right)^{-4}=\left(\frac{1}{3}\right)^{3-4}=\left(\frac{1}{3}\right)^{-1}=3^1\)

20 tháng 9 2015

d,\(=\frac{1}{3^2}\cdot\frac{1}{3}\cdot\left(3^2\right)^2=\frac{3^4}{3^3}=3\)

20 tháng 9 2015

b,\(=2^2\cdot2^5:\left(2^3\cdot\frac{1}{2^4}\right)=2^7:\frac{1}{2}=2^7\cdot2=2^8\)

30 tháng 9 2016

a)\(\left(\frac{1}{5}\right)^{3n-1}=\frac{1}{25}\)

\(\Leftrightarrow\left(\frac{1}{5}\right)^{3n-1}=\left(\frac{1}{5}\right)^2\)

\(\Leftrightarrow3n-1=2\)

\(\Leftrightarrow3n=3\)

\(\Leftrightarrow n=1\)

b)\(\left(\frac{4}{7}\right)^{n+2}=\frac{7}{4}\)

\(\Leftrightarrow\left(\frac{4}{7}\right)^{n+2}=\left(\frac{4}{7}\right)^{-1}\)

\(\Leftrightarrow n+2=-1\)

\(\Leftrightarrow n=-3\)

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

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

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

\(\Leftrightarrow-n+1=-3\)

\(\Leftrightarrow n=-4\)

c)\(\left(0,7\right)^{3n+1}=10^3:7^3\)

\(\Leftrightarrow\left(\frac{7}{10}\right)^{3n+1}=\left(\frac{10}{7}\right)^3\)

\(\Leftrightarrow\left(\frac{7}{10}\right)^{3n+1}=\left(\frac{7}{10}\right)^{-3}\)

\(\Leftrightarrow3n+1=-3\)

\(\Leftrightarrow3n=-4\)

\(\Leftrightarrow n=-\frac{4}{3}\)