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16 tháng 6 2019

#)Giải :

Câu 2 :

Ta có : \(\frac{1}{9^5}=\frac{1}{\left(3^2\right)^5}=\frac{1}{3^{10}}\)

Vì \(\frac{1}{3^5}=\frac{1}{3^5}\Rightarrow\frac{1}{3^5}=\frac{1}{9^5}\)

311:5+311 .3/310.22(Câu 1)

\(=\frac{8.3^{11}}{3^{10}.4}=6\)

1/310 : 1/95   (Câu 2)

\(=\frac{1}{3^{10}}.3^{10}=1\)

(-25/36)5:5/6 (câu 3)

\(=\frac{-5^5}{6^{10}}.\frac{6^2}{5}=-\frac{5^4}{6^8}\)

15: A= 1/3-3/4+3/5+1/2007-1/36+1/15-2/9

Sửa đề: 

A=-3/4-2/9-1/36+1/3+3/5+1/15+1/2007

=-27/36-8/36-1/36+5/15+9/15+1/15+1/2007

=-1+1+1/2007=1/2007

16:

\(A=\dfrac{1}{3}+\dfrac{3}{5}+\dfrac{1}{15}-\dfrac{3}{4}-\dfrac{2}{9}-\dfrac{1}{36}+\dfrac{1}{64}\)

\(=\dfrac{5+9+1}{15}+\dfrac{-27-8-1}{36}+\dfrac{1}{64}\)

=1/64

17:

=1/2-1/2+2/3-2/3+3/4-3/4+4/5-4/5+5/6-5/6-6/7

=-6/7

19 tháng 6 2019

\(\frac{3^{11}\div5+3^{11}.3}{3^{10}.2^2}=\frac{3^{11}\cdot\frac{1}{5}+3^{11}\cdot3}{3^{10}.2^2}\)

                                  \(=\frac{3^{11}.\left(\frac{1}{5}+3\right)}{3^{10}.2^2}=\frac{3^{11}.\frac{16}{5}}{3^{10}.2^2}=\frac{\frac{48}{5}}{2^2}=\frac{48}{5}\cdot\frac{1}{4}=\frac{12}{5}\)

\(\frac{1}{3^{10}}\div\frac{1}{9^5}=\frac{1}{3^{10}}\div\frac{1}{3^{10}}=1\)

1:

a: =7/5(40+1/4-25-1/4)-1/2021

=21-1/2021=42440/2021

b: =5/9*9-1*16/25=5-16/25=109/25

10 tháng 12 2023

1: \(\dfrac{11}{24}-\dfrac{5}{41}+\dfrac{13}{24}+0,5-\dfrac{36}{41}\)

\(=\left(\dfrac{11}{24}+\dfrac{13}{24}\right)-\left(\dfrac{5}{41}+\dfrac{36}{41}\right)+\dfrac{1}{2}\)

\(=1-1+\dfrac{1}{2}=\dfrac{1}{2}\)

2: \(12:\left(\dfrac{3}{4}-\dfrac{5}{6}\right)^2\)

\(=12:\left(\dfrac{9}{12}-\dfrac{10}{12}\right)^2\)

\(=12:\left(-\dfrac{1}{12}\right)^2=12:\dfrac{1}{144}=12\cdot144=1368\)

3: \(\left(1+\dfrac{2}{3}-\dfrac{1}{4}\right)\cdot\left(0,8-\dfrac{3}{4}\right)^2\)

\(=\dfrac{12+8-3}{12}\cdot\left(\dfrac{4}{5}-\dfrac{3}{4}\right)^2\)

\(=\dfrac{17}{12}\cdot\left(\dfrac{16-15}{20}\right)^2\)

\(=\dfrac{17}{12}\cdot\dfrac{1}{400}=\dfrac{17}{4800}\)

4: \(16\dfrac{2}{7}:\left(-\dfrac{3}{5}\right)+28\dfrac{2}{7}:\dfrac{3}{5}\)

\(=\dfrac{5}{3}\cdot\left(-16-\dfrac{2}{7}\right)+\dfrac{5}{3}\cdot\left(28+\dfrac{2}{7}\right)\)

\(=\dfrac{5}{3}\left(-16-\dfrac{2}{7}+28+\dfrac{2}{7}\right)\)

\(=12\cdot\dfrac{5}{3}=20\)

5: \(\left(2^2:\dfrac{4}{3}-\dfrac{1}{2}\right)\cdot\dfrac{6}{5}-17\)

\(=\left(4\cdot\dfrac{3}{4}-\dfrac{1}{2}\right)\cdot\dfrac{6}{5}-17\)

\(=\dfrac{5}{2}\cdot\dfrac{6}{5}-17=3-17=-14\)

6: \(\left(\dfrac{1}{3}\right)^{50}\cdot\left(-9\right)^{25}-\dfrac{2}{3}:4\)

\(=\left(\dfrac{1}{3}\right)^{50}\cdot\left(-1\right)\cdot3^{50}-\dfrac{2}{3\cdot4}\)

\(=-1-\dfrac{2}{12}=-1-\dfrac{1}{6}=-\dfrac{7}{6}\)

19 tháng 12 2016
2qwert
19 tháng 12 2016

Câu 1 :So Sánh

\(3^{34}\text{và }5^{20}\)

\(\Leftrightarrow3^{34}>5^{20}\)

Câu 2 : Tìm chữ số tận cùng 

\(3^{25}\text{có tận cùng là 3}\)

\(9^{27}\text{có tận cùng là 9}\)

Học tốt

14 tháng 7 2017

x+1/3=2/5-(-1/3)

x+1/3=2/5+1/3

x=2/5+(1/3-1/3)

x=2/5

15 tháng 7 2017

x+1/3=2/5-(-1/3)

x+1/3=2/5+1/3

x=2/5+(1/3-1/3)

x=1/3