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23 tháng 7 2022

\(\dfrac{5}{4x13}\)+\(\dfrac{5x7}{4x13}\)\(\dfrac{10}{13}\)

=\(\dfrac{5}{4x13}\)\(\dfrac{5}{13}\)x(\(\dfrac{7}{4}\)+2)

=\(\dfrac{5}{13}\)(\(\dfrac{1}{4}\)+\(\dfrac{7}{4}\)+2)

=\(\dfrac{5}{13}\)x4

=\(\dfrac{20}{13}\)

23 tháng 4 2021

viết p/s như nào vậy bạn

23 tháng 4 2021

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a: \(=\dfrac{37}{4}+\dfrac{117}{16}+\dfrac{1}{4}=\dfrac{19}{2}+\dfrac{117}{16}=\dfrac{269}{16}\)

b: \(=1+\left(\dfrac{9}{10}+\dfrac{8}{10}\right):\dfrac{19}{6}=1+\dfrac{17}{10}\cdot\dfrac{6}{19}=\dfrac{146}{95}\)

c: \(=\dfrac{1}{4}-\dfrac{6}{4}+\dfrac{6}{5}=\dfrac{-5}{4}+\dfrac{6}{5}=\dfrac{-1}{20}\)

13 tháng 12 2022

( 2x -1)2 - \(\dfrac{1}{4}\) = 2                            ( -2\(\dfrac{1}{5}\)  + \(\dfrac{2}{7}\) - \(\dfrac{12}{13}\)) - ( - \(\dfrac{5}{7}\)+\(\dfrac{1}{13}\))

(2x -1)2        = 2 + \(\dfrac{1}{4}\)                   =     -\(\dfrac{11}{5}\) + \(\dfrac{2}{7}\) - \(\dfrac{12}{13}\) + \(\dfrac{5}{7}\) - \(\dfrac{1}{13}\)

(2x -1) 2        = \(\dfrac{9}{4}\)                         = - \(\dfrac{11}{5}\) + ( \(\dfrac{2}{7}+\dfrac{5}{7}\)) - ( \(\dfrac{12}{13}+\dfrac{1}{13}\))

\(\left[{}\begin{matrix}2x-1=\dfrac{3}{2}\\2x-1=-\dfrac{3}{2}\end{matrix}\right.\)                          = - \(\dfrac{11}{5}\) + 1 - 1

\(\left[{}\begin{matrix}2x=\dfrac{3}{2}+1\\2x=-\dfrac{3}{2}+1\end{matrix}\right.\)                          = -11/5 

\(\left[{}\begin{matrix}2x=2,5\\2x=-0,5\end{matrix}\right.\)

\(\left[{}\begin{matrix}x=1,25\\x=-0,25\end{matrix}\right.\)    

a: \(A=\dfrac{7}{12}+\dfrac{5}{72}-\dfrac{11}{36}=\dfrac{42}{72}+\dfrac{5}{72}-\dfrac{22}{72}=\dfrac{25}{72}\)

b: \(B=\dfrac{8+5}{10}:\dfrac{-5}{13}=\dfrac{13}{10}\cdot\dfrac{13}{-5}=-\dfrac{169}{100}\)

c: \(C=\left(\dfrac{88}{132}-\dfrac{33}{132}+\dfrac{60}{132}\right):\left(\dfrac{55}{132}+\dfrac{132}{132}-\dfrac{84}{132}\right)\)

\(=\dfrac{88-33+60}{55+132-84}=\dfrac{115}{103}\)

13: \(=\dfrac{4}{9}\cdot\left(-7\right)+\left(6+\dfrac{5}{9}\right)\cdot\left(-7\right)\)

\(=\left(-7\right)\left(\dfrac{4}{9}+6+\dfrac{5}{9}\right)=\left(-7\right)\cdot7=-49\)

14: \(=\left(\dfrac{-3}{4}+\dfrac{5}{13}\right)\cdot\dfrac{7}{2}-\left(\dfrac{9}{4}+\dfrac{8}{13}\right)\cdot\dfrac{7}{2}\)

\(=\dfrac{7}{2}\left(-\dfrac{3}{4}+\dfrac{5}{13}-\dfrac{9}{4}-\dfrac{8}{13}\right)\)

\(=\dfrac{7}{2}\left(-3-\dfrac{3}{13}\right)=\dfrac{7}{2}\cdot\dfrac{-42}{13}=\dfrac{-147}{13}\)

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

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

=1/64

 

20 tháng 12 2021

e: \(=\dfrac{5^{30}\cdot3^{20}}{3^{15}\cdot5^{30}}=3^5=243\)

1: Ta có: \(23\dfrac{1}{4}\cdot\dfrac{7}{5}-13\dfrac{1}{4}:\dfrac{5}{7}\)

\(=\dfrac{93}{4}\cdot\dfrac{7}{5}-\dfrac{53}{4}\cdot\dfrac{7}{5}\)

\(=\dfrac{7}{5}\cdot10=14\)

2: Ta có: \(\left(1+\dfrac{2}{3}-\dfrac{1}{4}\right)\left(\dfrac{4}{5}-\dfrac{3}{4}\right)^2\)

\(=\dfrac{12+8-3}{12}\cdot\dfrac{1}{400}\)

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

23 tháng 8 2023

\(=\left(-\dfrac{3}{4}+\dfrac{5}{13}\right).\dfrac{7}{2}-\left(\dfrac{9}{4}+\dfrac{8}{13}\right).\dfrac{7}{2}\\ =\dfrac{7}{2}\left(-\dfrac{3}{4}+\dfrac{5}{13}-\dfrac{9}{4}-\dfrac{8}{13}\right)\\ =\dfrac{7}{2}\left(-\dfrac{12}{4}-\dfrac{3}{13}\right)\\ =\dfrac{7}{2}\left(-3-\dfrac{3}{13}\right)\\ =\dfrac{7}{2}\left(-\dfrac{39}{13}-\dfrac{3}{13}\right)\\ =\dfrac{7}{2}\left(-\dfrac{42}{13}\right)\\ =\dfrac{7.\left(-42\right)}{2.13}\\ =-\dfrac{147}{13}\)