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25 tháng 7 2018

= 2*(1/7+1/17+1/37)

/5*(1/7+1/17+1/37)  +  3/5

= 2/5+3/5

=1

25 tháng 7 2018

\(F=\frac{\frac{2}{7}+\frac{2}{17}+\frac{2}{37}}{\frac{5}{7}+\frac{5}{17}+\frac{5}{37}}+\frac{3}{5}\)

\(\Rightarrow F=\frac{2\left(\frac{1}{7}+\frac{1}{17}+\frac{1}{37}\right)}{5\left(\frac{1}{7}+\frac{1}{17}+\frac{1}{37}\right)}+\frac{3}{5}\)

\(\Rightarrow F=\frac{2}{5}+\frac{3}{5}=\frac{5}{5}=1\)

5 tháng 7 2016

\(A=\frac{\frac{3}{7}-\frac{3}{17}+\frac{3}{37}}{\frac{5}{7}-\frac{5}{17}+\frac{5}{37}}+\frac{\frac{1}{2}-\frac{1}{3}+\frac{1}{4}-\frac{1}{5}}{\frac{7}{5}-\frac{7}{4}+\frac{7}{3}-\frac{7}{2}}\)

\(=\frac{3\left(\frac{1}{7}-\frac{1}{17}-\frac{1}{37}\right)}{5\left(\frac{1}{7}-\frac{1}{17}-\frac{1}{37}\right)}+\frac{1.\left(\frac{1}{2}-\frac{1}{3}+\frac{1}{4}-\frac{1}{5}\right)}{-7\left(\frac{1}{2}-\frac{1}{3}+\frac{1}{4}-\frac{1}{5}\right)}\)

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

\(=\frac{21}{35}-\frac{5}{35}\)

\(=\frac{16}{35}\)

5 tháng 7 2016

\(A=\frac{3.\left(\frac{1}{7}-\frac{1}{17}-\frac{1}{37}\right)}{5.\left(\frac{1}{7}-\frac{1}{17}-\frac{1}{37}\right)}+\frac{\frac{1}{2}-\frac{1}{3}+\frac{1}{4}-\frac{1}{5}}{7.\left(\frac{1}{2}-\frac{1}{3}+\frac{1}{4}-\frac{1}{5}\right)}\)

\(A=\frac{3}{5}+\frac{1}{7}=\frac{21}{35}+\frac{5}{35}=\frac{26}{35}\)

\(1\frac{3}{5}+\left(\frac{\frac{2}{7}+\frac{2}{17}+\frac{2}{37}}{\frac{5}{7}+\frac{5}{17}+\frac{5}{37}}\right)x=\frac{16}{5}\)

\(\Rightarrow\frac{2\left(\frac{1}{7}+\frac{1}{17}+\frac{1}{37}\right)}{5\left(\frac{1}{7}+\frac{1}{17}+\frac{1}{37}\right)}.x=\frac{16}{5}-\frac{8}{5}\)

\(\Rightarrow\frac{2}{5}.x=\frac{8}{5}\)

\(\Rightarrow x=\frac{8}{5}:\frac{2}{5}=4\)

vậy x=4

10 tháng 8 2015

\(\frac{7}{5}+\left(\frac{2\left(\frac{1}{7}+\frac{1}{17}+\frac{1}{37}\right)}{5\left(\frac{1}{7}+\frac{1}{17}+\frac{1}{37}\right)}\right)\cdot x=\frac{16}{5}\)

\(\frac{2}{5}x=\frac{16}{5}-\frac{7}{5}\)

\(\frac{2}{5}x=\frac{9}{5}\)

 x      = \(\frac{9}{5}:\frac{2}{5}\)

x        = 9/2 

10 tháng 8 2015

\(1\frac{2}{5}+\left(\frac{\frac{2}{7}+\frac{2}{17}+\frac{2}{37}}{\frac{5}{7}+\frac{5}{17}+\frac{5}{37}}\right).x=\frac{16}{5}\)

\(\frac{7}{5}+\left[\frac{2.\left(\frac{1}{7}+\frac{1}{17}+\frac{1}{37}\right)}{5.\left(\frac{1}{7}+\frac{1}{17}+\frac{1}{37}\right)}\right].x=\frac{16}{5}\)

\(\frac{7}{5}+\frac{2}{5}.x=\frac{16}{5}\)

\(\frac{2}{5}.x=\frac{16}{5}-\frac{7}{5}\)

\(\frac{2}{5}.x=\frac{9}{5}\)

\(x=\frac{9}{5}:\frac{2}{5}\)

\(x=\frac{9}{5}.\frac{5}{2}\)

\(x=\frac{9}{2}\)

11 tháng 5 2015

=.8/5+((2*17*37+2*7*37+2*7*17)/(7*17*37))/((5*17*37+5*7*37+5*7*17)/(7*17*37))*x=16/5

=>8/5+((2*17*37+2*7*37+2*7*17)/(7*17*37))*((7*17*37)/(5*17*37+5*7*37+5*7*17))*x=16/5

=>8/5+(2(17*37+7*37+7*17))/(5(17*37+7*37+7*17))*x=16/5

=>8/5+(2/5)*x=16/5

=>(2/5)*x=16/5-8/5

=>(2/5)*x=8/5

=>x=(8/5)/(2/5)

=>x=4

Vậy x=4

11 tháng 5 2015

ngothithuyhien  làm dài dòng quá !

15 tháng 7 2015

Nhiều quá...................

a)\(\left(\frac{1}{24.25}+\frac{1}{25.26}+...+\frac{1}{29.30}\right).120+x:\frac{1}{3}=-4\)

\(\Rightarrow\left(\frac{1}{24}-\frac{1}{25}+\frac{1}{25}-\frac{1}{26}+...+\frac{1}{29}-\frac{1}{30}\right).120+x:\frac{1}{3}=-4\)

\(\Rightarrow\left(\frac{1}{24}-\frac{1}{30}\right).120+x:\frac{1}{3}=-4\)

\(\Rightarrow\frac{1}{120}.120+x:\frac{1}{3}=-4\)

\(\Rightarrow1+x:\frac{1}{3}=-4\)

\(\Rightarrow x:\frac{1}{3}=-4-1=-5\)

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

b)\(1\frac{3}{5}+\left(\frac{\frac{2}{7}+\frac{2}{17}+\frac{2}{37}}{\frac{5}{7}+\frac{5}{17}+\frac{5}{37}}\right).x=\frac{16}{5}\)

\(\Rightarrow\frac{8}{5}+\left[\frac{2.\left(\frac{1}{7}+\frac{1}{17}+\frac{1}{37}\right)}{5.\left(\frac{1}{7}+\frac{1}{17}+\frac{1}{37}\right)}\right].x=\frac{16}{5}\)

\(\Rightarrow\frac{8}{5}+\frac{2}{5}.x=\frac{16}{5}\)

\(\Rightarrow\frac{2}{5}.x=\frac{16}{5}-\frac{8}{5}=\frac{8}{5}\)

\(\Rightarrow x=\frac{8}{5}:\frac{2}{5}=\frac{8}{5}.\frac{5}{2}=\frac{8}{2}=4\)

\(\Rightarrow x=4\)

11 tháng 5 2020

Phải là \(B=\frac{0,5-\frac{3}{17}+\frac{3}{37}}{\frac{5}{6}-\frac{5}{7}+\frac{5}{37}}+\frac{0,5-\frac{1}{3}+\frac{1}{4}-0,2}{\frac{7}{5}-\frac{7}{4}+\frac{7}{3}-3,5}\)  chứ nhỉ?

Nếu đúng thì phân tích như sau

\(\Leftrightarrow B=\frac{\frac{3}{6}-\frac{3}{17}+\frac{3}{37}}{\frac{5}{6}-\frac{5}{7}+\frac{5}{37}}+\frac{\frac{1}{2}-\frac{1}{3}+\frac{1}{4}-\frac{1}{5}}{\frac{7}{5}-\frac{7}{4}+\frac{7}{3}-\frac{7}{2}}\)

\(B=\frac{3\left(\frac{1}{6}-\frac{1}{17}+\frac{1}{37}\right)}{5\left(\frac{1}{6}-\frac{1}{17}+\frac{1}{37}\right)}+\frac{\frac{1}{2}-\frac{1}{3}+\frac{1}{4}-\frac{1}{5}}{7\left(\frac{1}{2}-\frac{1}{3}+\frac{1}{4}-\frac{1}{5}\right)}\)

\(B=\frac{3}{5}+\frac{1}{7}=\frac{16}{35}\)

15 tháng 4 2019

\(\frac{\frac{2}{7}+\frac{2}{17}+\frac{2}{37}}{\frac{5}{7}+\frac{5}{17}+\frac{5}{37}}\)

\(=\frac{2\left(\frac{1}{7}+\frac{1}{17}+\frac{1}{37}\right)}{5\left(\frac{1}{7}+\frac{1}{17}+\frac{1}{37}\right)}\)

\(=\frac{2}{5}\)

2/7+2/17+2/37/ 5/7+5/17+5/37

= 2(1/7+1/17+1/37)/ 5(1/7+1/17+1/37)

= 2/5

# HỌC TỐT #

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