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7 tháng 9 2017

63+3x62+33/13

=63+31x62+33/13

=62x31x(6+32)/13

=1620/13

Em nghĩ là thế !

7 tháng 9 2017

bài này ra 27 

24 tháng 6 2017

= (2.3)^3+ 3. ( 2.3)^2 + 3^3 / -13

= 2^3 .3^3 + 3. 3^2 . 2^2 + 3^3 / -13

= 3^3. ( 2^3 + 2^2 + 1) /-13

= 27.13/-13

= -27

24 tháng 6 2017

\(\frac{6^3+3\cdot6^2+3^3}{-13}=\frac{6^2\left(6+3\right)+3^2\cdot3}{-13}=\frac{36\cdot9+9\cdot3}{-13}=\frac{39\cdot9}{-13}=-3\cdot9=-27\)

\(\dfrac{x+4}{2000}+\dfrac{x+3}{2001}=\dfrac{x+2}{2002}+\dfrac{x+1}{2003}\)

1/* Chứng minh rằng:

\(\dfrac{1}{1\times2}+\dfrac{1}{3\times4}+\dfrac{1}{5\times6}+...\dfrac{1}{49\times50}=\dfrac{1}{26}+\dfrac{1}{27}+\dfrac{1}{28}+..+\dfrac{1}{50}\)

2/* Cho:

A=\(\dfrac{1}{1\times2}+\dfrac{1}{3\times4}+\dfrac{1}{5\times6}+.....+\dfrac{1}{99\times100}\). Chứng minh rằng:\(\dfrac{7}{12}< A>\dfrac{5}{6}\)

Các bn giúp mk những bài này nha!

4
16 tháng 7 2017

\(\dfrac{x+4}{2000}+\dfrac{x+3}{2001}=\dfrac{x+2}{2002}+\dfrac{x+1}{2003}\)

\(\Rightarrow\dfrac{x+4}{2000}+1+\dfrac{x+3}{2001}+1=\dfrac{x+2}{2002}+1+\dfrac{x+1}{2003}+1\)

\(\Rightarrow\dfrac{x+2004}{2000}+\dfrac{x+2004}{2001}=\dfrac{x+2004}{2002}+\dfrac{x+2004}{2003}\)

\(\Rightarrow\dfrac{x+2004}{2000}+\dfrac{x+2004}{2001}-\dfrac{x+2004}{2002}-\dfrac{x+2004}{2003}=0\)

\(\Rightarrow\left(x+2004\right)\left(\dfrac{1}{2000}+\dfrac{1}{2001}-\dfrac{1}{2002}-\dfrac{1}{2003}\right)=0\)

\(\Rightarrow x+2004=0\Rightarrow x=-2004\)

16 tháng 7 2017

\(\dfrac{x+4}{2000}+\dfrac{x+3}{2001}=\dfrac{x+2}{2002}+\dfrac{x+1}{2003}\)

\(\Rightarrow\dfrac{x+4}{2000}+\dfrac{x+3}{2001}-\dfrac{x+2}{2002}-\dfrac{x+1}{2003}=0\)

\(\Rightarrow\dfrac{x+4}{2000}+1+\dfrac{x+3}{2001}+1-\dfrac{x+2}{2002}-1-\dfrac{x+1}{2003}-1=0\)

\(\Rightarrow\dfrac{x+2004}{2000}+\dfrac{x+2004}{2001}-\dfrac{x+2004}{2002}-\dfrac{x+2004}{2003}=0\)

\(\Rightarrow x+2004\left(\dfrac{1}{2000}+\dfrac{1}{2001}-\dfrac{1}{2002}-\dfrac{1}{2003}\right)=0\)

\(\Rightarrow x+2004=0\)

\(\Rightarrow x=-2004\)

Vậy \(x=-2004\)

3 tháng 8 2017

a, \(\dfrac{20^5.5^{10}}{100^5}=\dfrac{20^5.5^{10}}{\left(20.5\right)^5}=\dfrac{20^5.5^{10}}{20^5.5^5}=5^5\)

3 tháng 8 2017

b,\(\dfrac{\left(0,9\right)^5}{\left(0,3\right)^6}=\dfrac{\left(0,3.3\right)^5}{\left(0,3\right)^6}=\dfrac{\left(0,3\right)^5.3^5}{\left(0,3\right)^6}=\dfrac{3^5}{\left(0,3\right)}\)

13 tháng 9 2016

\(\frac{2^7.3^6}{6^5.8^2}\)\(\frac{2^7.3^6}{3^5.2^5.2^6}\)=\(\frac{2^7.3^6}{3^5.2^{11}}\)=\(\frac{3}{2^4}\)=\(\frac{3}{16}\)

đó là ý kiến của mình

13 tháng 9 2016

\(a.\frac{2^7\times9^3}{6^5\times8^2}\)

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

\(b.\frac{6^3+3\times6^2+3^3}{-13}\)

\(-\frac{333}{13}\)

7 tháng 8 2015

\(\frac{4^2\times4^3}{2^{10}}=\frac{\left(2^2\right)^2\times\left(2^2\right)^3}{2^{10}}=\frac{2^4\times2^6}{2^{10}}=\frac{2^{10}}{2^{10}}=1\)

\(\frac{\left(0,6\right)^5}{\left(0,2\right)^6}=\frac{\left(0,2\times3\right)^5}{\left(0,2\right)^6}=\frac{\left(0,2\right)^5\times3^5}{\left(0,2\right)^6}=\frac{3^5}{0,2}=\frac{243}{0,2}=243:\left(0,2\right)=243\times5=1215\)

\(\frac{2^7\times9^3}{6^5\times8^2}=\frac{2^7\times\left(3^2\right)^3}{\left(2\times3\right)^5\times\left(2^3\right)^2}=\frac{2^7\times3^6}{2^5\times3^5\times2^6}=\frac{3}{2^4}=\frac{3}{16}\)

\(\frac{6^3+3\times6^2+3^3}{-13}=\frac{\left(2\times3\right)^3+3\times6^2+3^3}{-13}=\frac{3\left(2^3\times3^2+6^2+3^2\right)}{-13}=\frac{3\times117}{-13}=\frac{351}{-13}=-27\)

22 tháng 9 2019

\(\frac{\left(-0,25\right)^{-5}.9^4.\left(-2\right)^{-3}-2^{-2}.6^9}{2^9.3^6+6^6.40}\)

\(=\frac{\left(-4\right)^5.\left(3^2\right)^4.\left(-2\right)^{-3}-2^{-2}.\left(3.2\right)^9}{2^9.3^6+\left(2.3\right)^6.2^3.5}\)

\(=\frac{-\left(2^2\right)^5.3^8.\left(-2\right)^{-3}-2^{-2}.3^9.2^9}{2^9.3^6+2^6.3^6.2^3.5}\)

\(=\frac{-2^{10}3^8.\left(-2\right)^{-3}-2^7.3^9}{2^9.3^6+2^9.3^6.5}\)

\(=\frac{2^73^8.-2^7.3^9}{2^9.3^6+2^9.3^6.5}\)

\(=\frac{2^7.3^8.\left(1-3\right)}{2^9.3^6.\left(1+5\right)}\)

\(=\frac{3^2.\left(-2\right)}{2^2.6}\)

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

8 tháng 8 2015

d)\(\frac{6^3+3\cdot6^2+3^3}{-13}=\frac{3^3\cdot2^3+3^3\cdot2^2+3^3}{-13}=\frac{3^3\left(8+4+1\right)}{-13}=\frac{3^3\cdot13}{-13}=-27\)

giang làm a,b,c rồi nên làm d thôi

lười quá, hehe ^_^

8 tháng 8 2015

a) \(\frac{4^2\cdot4^3}{2^{10}}=\frac{\left(2^2\right)^2.\left(2^2\right)^3}{2^{10}}=\frac{2^4.2^6}{2^{10}}=\frac{2^{10}}{2^{10}}=1\)

b)\(\frac{\left(0,6\right)^5}{\left(0,2\right)^6}=\frac{\left(0,2.3\right)^5}{\left(0,2\right)^6}=\frac{\left(0,2\right)^5.3^5}{\left(0,2\right)^6}=\frac{3^5}{0,2}=\frac{243.5}{1}=1215\)

c)\(\frac{2^7.9^3}{6^5.8^2}=\frac{2^7.\left(3^2\right)^3}{\left(2.3\right)^5.\left(2^3\right)^2}=\frac{2^7.3^6}{2^5.3^5.2^6}=\frac{2^7.3^5}{2^{11}.3^5}=\frac{1}{2^4}=\frac{1}{16}\)