\(\frac{3}{7}\))\(^{21}\): ( \(\fr...">
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25 tháng 7 2016

a) \(\left(\frac{3}{7}\right)^{21}:\left(\frac{9}{47}\right)^6=\left(\frac{3}{7}\right)^{21}:\left[\left(\frac{3}{7}\right)^2\right]^6=\left(\frac{3}{7}\right)^{21}:\left(\frac{3}{7}\right)^{12}=\left(\frac{3}{7}\right)^{21-12}=\left(\frac{3}{7}\right)^9\)

b) \(\frac{390}{130}^4=3^4=81\)

c) \(\left(0,125\right)^3.512=\frac{1}{512}.512=1\)

14 tháng 8 2017

image /assets/images/2017/08_10/1195-xHOKk8NXdv5EDVJo.jpeg

14 tháng 8 2017

a) \(\left(\dfrac{1}{5}\right)^5.5^5=\left(\dfrac{1}{5}.5\right)^5=1^5=1\)

b) \(\left(0,125\right)^3.512=\left(0,512\right)^3.8^3=\left(0,512.8\right)^3=1^3=1\)

c) \(\left(0,25\right)^4.1024=\left[\left(0,25\right)^2\right]^2.32^2=\left(\dfrac{1}{6}\right)^2.32^2=\left(\dfrac{1}{6}.32\right)^2=2^2=4\)

d) \(\dfrac{120^3}{40^3}=\left(\dfrac{120}{40}\right)^3=3^3=64\)

e) \(\dfrac{390^4}{130^4}=\left(\dfrac{390}{130}\right)^4=3^4=81\)

g) \(\dfrac{3^2}{\left(0,375\right)^2}=\left(\dfrac{3}{0,375}\right)^3=8^3=512\)

26 tháng 6 2019

1. sai dấu nhé 

2.a, \(\frac{45^{10}.5^{20}}{75^{15}}=\frac{\left(3^2.5\right)^{10}.5^{20}}{\left(5^2.3\right)^{15}}=\frac{3^{20}.5^{30}}{5^{30}.3^{15}}=3^5=243\)

b, \(\frac{\left(0,8\right)^5}{\left(0,4\right)^6}=\frac{\left(\frac{4}{5}\right)^5}{\left(\frac{2}{5}\right)^6}=\frac{\left(\frac{2}{5}\cdot2\right)^5}{\left(\frac{2}{5}\right)^6}=\frac{\left(\frac{2}{5}\right)^5\cdot2^5}{\left(\frac{2}{5}\right)^5\cdot\frac{2}{5}}=2^5\div\frac{2}{5}=32\cdot\frac{5}{2}=80\)

c, \(\frac{2^{15}.9^4}{6^6.8^3}=\frac{2^{15}.3^8}{2^6.3^6.2^9}=\frac{2^{15}.3^2}{2^{15}}=3^2=9\)

14 tháng 7 2016

làm 1 bài mẫu nha

a) \(\left(\frac{1}{3}.x\right):\frac{2}{3}=\frac{25}{6}\)

\(\Rightarrow\frac{1}{3}x=\frac{25}{9}\)

\(\Rightarrow x=\frac{25}{9}:\frac{1}{3}\)

\(\Rightarrow x=\frac{25}{3}\)

các bài sau dễ lắm

a) \(\left(\frac{1}{3}x\right):\frac{2}{3}=1\frac{2}{3}:\frac{2}{5}\)

\(\Rightarrow\frac{1}{3}x:\frac{2}{3}=\frac{25}{6}\)

\(\Rightarrow\frac{1}{3}x=\frac{5}{3}\)

\(\Rightarrow x=\frac{5}{3}:\frac{1}{3}\)

\(\Rightarrow x=5\)

17 tháng 7 2016

33 = 27

34= 81

82= 64

9 tháng 4 2020

a) \(\frac{21}{47}+\frac{9}{45}+\frac{26}{47}+\frac{4}{5}\)

\(=\left(\frac{21}{47}+\frac{26}{47}\right)+\left(\frac{9}{45}+\frac{4}{5}\right)\)

\(=\frac{47}{47}+\left(\frac{1}{5}+\frac{4}{5}\right)\)

\(=1+1=2\)

b) \(12.\left(-\frac{2}{3}\right)^2+\frac{4}{3}\)

\(=12.\frac{4}{9}+\frac{4}{3}\)

\(=\frac{16}{3}+\frac{4}{3}\)

\(=\frac{20}{3}\)

c) \(12,5.\left(-\frac{5}{7}\right)+15.\left(-\frac{5}{7}\right)\)

\(=\left(-\frac{5}{7}\right).\left(12,5+15\right)\)

\(=\left(-\frac{5}{7}\right).27,5\)

\(=\left(-\frac{5}{7}\right).\frac{55}{2}\)

\(=-\frac{275}{14}\)

d) \(\frac{4}{5}.\left(\frac{7}{2}+\frac{1}{4}\right)^2\)

\(=\frac{4}{5}.\left(\frac{14}{4}+\frac{1}{4}\right)^2\)

\(=\frac{4}{5}.\left(\frac{15}{4}\right)^2\)

\(=\frac{4}{5}.\frac{225}{16}\)

\(=\frac{45}{4}\)

9 tháng 4 2020

a)\(\frac{21}{47}+\frac{9}{45}+\frac{26}{47}+\frac{4}{5}\)

=\(\frac{21}{47}+\frac{1}{5}+\frac{26}{47}+\frac{4}{5}\)

=\(\left(\frac{21}{47}+\frac{26}{47}\right)+\left(\frac{1}{5}+\frac{4}{5}\right)\)

=\(\frac{47}{47}+\frac{5}{5}=1+1=2\)

b)\(12.\left(-\frac{2}{3}\right)^2+\frac{4}{3}\)

=\(12.\frac{4}{9}+\frac{4}{3}\)

=\(\frac{12}{1}.\frac{4}{9}+\frac{4}{3}=\frac{48}{9}+\frac{4}{3}\)

=\(\frac{16}{3}+\frac{4}{3}=\frac{20}{3}\)

c)\(12,5.\left(-\frac{5}{7}\right)+1,5.\left(-\frac{5}{7}\right)\)

=\(\left(-\frac{5}{7}\right).\left(12,5+1,5\right)\)

=\(\left(-\frac{5}{7}\right).14=\left(-\frac{5}{7}\right).\frac{14}{1}=-10\)

d)\(\frac{4}{5}.\left(\frac{7}{2}+\frac{1}{4}\right)^2\)

=\(\frac{4}{5}.\left(\frac{14}{4}+\frac{1}{4}\right)^2\)

=\(\frac{4}{5}.\left(\frac{15}{4}\right)^2\)

=\(\frac{4}{5}.\frac{225}{16}\)

=\(\frac{900}{80}=\frac{45}{4}\)

Nhớ tick cho mình nha!banh

24 tháng 1 2017

a) 

\(=-\frac{1}{2187}.2187\)

\(=-1\)

b) 

\(=\frac{1}{512}.512\)

\(=1\)

c) 

\(=\frac{8100}{225}=36\)

d) \(=10000\)

24 tháng 1 2017

a, \(\left(\frac{-1}{3}\right)^7.3^7=-\frac{1}{2187}.2187=-1\)

b, \(\left(0,125\right)^3.512=\frac{1}{512}.512\)

                                  \(=1\)

c, \(\frac{90^2}{15^2}=\frac{8100}{225}\)

              \(=8100:225=36\)

d, \(\frac{790^4}{79^4}=\left(790:79\right)^4\)

                 \(=10^4=10000\)