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![](https://rs.olm.vn/images/avt/0.png?1311)
\(1.a,\frac{18}{24}:\frac{5}{2}+\frac{7}{-10}\)
\(=\frac{18}{24}:\frac{5}{2}+\frac{-7}{10}\)
\(=\frac{18}{24}\cdot\frac{2}{5}+\frac{-7}{10}\)
\(=\frac{3}{4}\cdot\frac{2}{5}+\frac{-7}{10}\)
\(=\frac{3}{2}\cdot\frac{1}{5}+\frac{-7}{10}\)
\(=\frac{3}{10}+\frac{-7}{10}=\frac{-4}{10}=\frac{-2}{5}\)
\(\left[\frac{12}{199}-\frac{23}{200}+\frac{34}{201}\right]\cdot\left[\frac{1}{2}-\frac{1}{3}-\frac{1}{6}\right]\)
\(=\left[\frac{12}{199}-\frac{23}{200}+\frac{34}{201}\right]\cdot\left[\frac{3}{6}-\frac{2}{6}-\frac{1}{6}\right]\)
\(=\left[\frac{12}{199}-\frac{23}{200}+\frac{34}{201}\right]\cdot\left[\frac{3-2-1}{6}\right]\)
\(=\left[\frac{12}{199}-\frac{23}{200}+\frac{34}{301}\right]\cdot0=0\)
2. \(a,x+5=15\Leftrightarrow x=15-5=10\)
\(b,x-\frac{5}{3}=\frac{1}{9}\)
\(\Leftrightarrow x=\frac{1}{9}+\frac{5}{3}\)
\(\Leftrightarrow x=\frac{1}{9}+\frac{15}{9}=\frac{16}{9}\)
c, Sửa lại đề một xíu :
\(\frac{x}{15}=\frac{-2}{3}+\frac{3}{5}\)
\(\Leftrightarrow\frac{x}{15}=\frac{-10}{15}+\frac{9}{15}\)
\(\Leftrightarrow\frac{x}{15}=\frac{-1}{15}\)
\(\Leftrightarrow x=-1\)
\(d,\frac{x}{9}< \frac{7}{x}< \frac{x}{6}(x\inℤ)\)
\(\frac{x\cdot x}{9\cdot x}< \frac{7\cdot9}{9\cdot x}< \frac{7\cdot6}{6\cdot x}\)
\(\Leftrightarrow\frac{x^2}{9x}< \frac{63}{9x}< \frac{42}{6x}\)
Tự làm nốt :>
![](https://rs.olm.vn/images/avt/0.png?1311)
=\(\left(\frac{12}{199}+\frac{23}{200}-\frac{34}{201}\right)\cdot\left(\frac{1}{2}-\frac{1}{3}-\frac{1}{6}\right)\)
=\(\left(\frac{12}{199}+\frac{23}{200}-\frac{34}{201}\right)\cdot\left(\frac{3}{6}-\frac{2}{6}-\frac{1}{6}\right)\)
=\(\left(\frac{12}{199}+\frac{23}{200}-\frac{34}{201}\right)\cdot0\)
\(=0\)
Kết quả = 0 nhé, nhớ ủng hộ mh, mh đang âm diểm
~ HOK TỐT ~
\(\left(\frac{12}{199}+\frac{23}{200}-\frac{34}{201}\right)\left(\frac{1}{2}-\frac{1}{3}-\frac{1}{6}\right)\)
\(=\left(\frac{12}{199}+\frac{23}{200}-\frac{34}{201}\right)\left(\frac{3}{6}-\frac{2}{6}-\frac{1}{6}\right)\)
\(=\left(\frac{12}{199}+\frac{23}{200}-\frac{34}{201}\right)\cdot0\)
\(=0\)
![](https://rs.olm.vn/images/avt/0.png?1311)
a) \(\left(\frac{-1}{6}+\frac{5}{-12}\right)+\frac{7}{12}=\left(\frac{-2}{12}+\frac{-5}{12}\right)+\frac{7}{12}=\left(\frac{-7}{12}\right)+\frac{7}{12}=0\)
b)\(\frac{7}{36}-\frac{8}{-9}+\frac{-2}{3}=\frac{7}{36}+\frac{32}{36}-\frac{24}{36}=\frac{15}{36}=\frac{5}{12}\)
c) \(\frac{3}{5}-\frac{2}{5}.\frac{10}{12}=\frac{3}{5}-\frac{2}{5}.\frac{5}{6}=\frac{3}{5}-\frac{1}{3}=\frac{9}{15}-\frac{5}{15}=\frac{4}{15}\)
d) \(\frac{2}{\left(-3\right)^2}+\frac{5}{-13}-\frac{-3}{4}=\frac{2}{9}-\frac{5}{13}+\frac{3}{4}=\frac{8}{36}-\frac{15}{36}+\frac{27}{36}=\frac{5}{9}\)
![](https://rs.olm.vn/images/avt/0.png?1311)
a) \(\left(2\frac{5}{6}+1\frac{4}{9}\right):\left(10\frac{1}{12}-9\frac{1}{2}\right)\)
\(=\left(\frac{17}{6}+\frac{13}{9}\right):\left(\frac{121}{12}-\frac{19}{2}\right)\)
\(=\frac{77}{18}:\frac{7}{12}\)
\(=\frac{22}{3}\)
b) \(1\frac{5}{18}-\frac{5}{18}.\left(\frac{1}{15}+1\frac{1}{12}\right)\)
\(=\frac{23}{18}-\frac{5}{18}.\left(\frac{1}{15}+\frac{13}{12}\right)\)
\(=\frac{23}{18}-\frac{5}{18}.\frac{23}{20}\)
\(=\frac{23}{18}-\frac{23}{72}\)
\(=\frac{23}{24}\)
c) \(-1\frac{1}{7}.\left(9\frac{1}{2}-8,75\right):\frac{2}{7}+0,625:1\frac{2}{3}\)
\(=\frac{-8}{7}.\left(\frac{19}{2}-\frac{35}{4}\right):\frac{2}{7}+\frac{5}{8}:\frac{5}{3}\)
\(=\frac{-8}{7}.\frac{3}{4}:\frac{2}{7}+\frac{3}{8}\)
\(=\frac{-8}{7}.\frac{3}{4}.\frac{7}{2}+\frac{3}{8}\)
\(=-3+\frac{3}{8}\)
\(=\frac{-21}{8}\)
Chúc bn học tốt !!