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Ta có : \(\frac{17}{-5}=-1-\frac{12}{5}\)
\(-\frac{6}{5}=-1-\frac{1}{5}\)
Mà : 1/5 < 12/5
=> \(\frac{-6}{5}>\frac{-15}{7}\)
Ta có:
<----+----+----+-+-+-+-+----+----+---->
-3 -2 -1;3/-4 0 1 2
Ta có\(-\frac{5}{91}=-\frac{505}{9191}\)
Mà \(-\frac{505}{9191}< -\frac{501}{9191}\)
Nên\(-\frac{5}{91}< -\frac{501}{9191}\)
a) \(\left(\frac{5}{25}-1,008\right):\frac{4}{7}:\left[\left(3\frac{1}{4}-6\frac{5}{9}\right)\cdot2\frac{2}{17}\right]\)
\(=\left(\frac{1}{5}-\frac{126}{125}\right):\frac{4}{7}:\left[\left(\frac{13}{4}-\frac{59}{9}\right)\cdot\frac{36}{17}\right]\)
\(=\left(\frac{25}{125}-\frac{126}{125}\right):\frac{4}{7}:\left[-\frac{119}{36}\cdot\frac{36}{17}\right]\)
\(=-\frac{101}{125}:\frac{4}{7}:\left(-7\right)=-\frac{101}{125}\cdot\frac{7}{4}\cdot\left(-\frac{1}{7}\right)=\frac{101}{500}\)
b) \(\left(-0,5-\frac{3}{5}\right):\left(-3\right)+\frac{1}{3}-\left(-\frac{1}{6}\right):\left(-2\right)\)
\(=\left(-\frac{1}{2}-\frac{3}{5}\right):\left(-3\right)+\frac{1}{3}-\left(-\frac{1}{6}\right)\cdot\left(-\frac{1}{2}\right)\)
\(=-\frac{11}{10}:\left(-3\right)+\frac{1}{3}-\frac{1}{12}\)
\(=\frac{11}{30}+\frac{1}{3}-\frac{1}{12}=\frac{37}{60}\)
a) \(\frac{1}{7}+\frac{6}{7}:\frac{3}{7}\)
\(=\frac{1}{7}+\frac{6}{7}.\frac{7}{3}\) (nhân nghịch đảo)
\(=\frac{1}{7}+2\)
\(=\frac{15}{7}\)
b) \(\frac{4}{5}-\frac{1}{5}.\left(-3\right)\)
\(=\frac{4}{5}-\left(-\frac{3}{5}\right)\)
\(=\frac{7}{5}\)
c) \(\frac{3}{7}+\left(\frac{-5}{2}\right)-\left(-\frac{3}{5}\right)\)
\(=\frac{3}{7}-\left(-\frac{5}{2}\right)+\frac{3}{5}\)
\(=\frac{30}{70}+\frac{175}{70}+\frac{42}{70}\)
\(=\frac{30+175+42}{70}\)
\(=\frac{247}{70}\)
d) viết lại đề hộ mình nhé
\(\frac{3\left(\frac{a}{b}\right)^2-1}{\left(\frac{a}{b}\right)^2+1}=\frac{3}{4}\Leftrightarrow12\left(\frac{a}{b}\right)^2-4=3.\left(\frac{a}{b}\right)^2+3\)\(\Leftrightarrow9\left(\frac{a}{b}\right)^2=1\Leftrightarrow\left(\frac{a}{b}\right)=+-\frac{\sqrt{3}}{3}\)
Ta có :
\(\frac{x}{3}:\frac{2}{3}=1\frac{3}{4}:\frac{2}{5}\)
\(\Rightarrow\frac{x}{3}:\frac{2}{3}=\frac{7}{4}:\frac{2}{5}\)
\(\Rightarrow\frac{x}{3}:\frac{2}{3}=\frac{35}{8}\)
\(\Rightarrow\frac{x}{3}=\frac{35}{8}.\frac{2}{3}=\frac{35.2}{8.3}=\frac{35}{12}\)
\(\Rightarrow\frac{x}{3}=\frac{35}{12}\)
\(\Rightarrow x=35:12.3=\frac{35}{4}\)