a) = 3/3 x ( -24/54 +45/54 ) : 7/12

   = 1 x 21/54 x 12/7

   = 18/27 

( hiện tại mik chỉ lm đc thế này thui. thông cảm nk )

S = \(\frac12\times\frac13\) + \(\frac13\times\frac14\) + \(\frac14\times\frac15\) + \(\frac15\times\frac16\) + \(\frac17\times\frac18\) + \(\frac18\times\frac19\)

S = \(\frac12\) - \(\frac13\) + \(\frac13\) - \(\frac14\) + \(\frac14\) - \(\frac15\) + \(\frac15\) - \(\frac16\) + \(\frac17\) - \(\frac18\) + \(\frac18\) - \(\frac19\)

S = \(\frac12\) - \(\frac19\)

S = \(\frac{9}{18}-\frac{2}{18}\)

S = \(\frac{7}{18}\)

a: \(\Leftrightarrow-\dfrac{9}{46}+\dfrac{108}{46}-\dfrac{93}{23}:\left(\dfrac{13}{4}-\dfrac{5}{3}x\right)=1\)

\(\Leftrightarrow\dfrac{93}{23}:\left(\dfrac{13}{4}-\dfrac{5}{3}x\right)=\dfrac{53}{46}\)

\(\Leftrightarrow-\dfrac{5}{3}x+\dfrac{13}{4}=\dfrac{186}{53}\)

=>-5/3x=55/212

hay x=-33/212

c: \(\Leftrightarrow\dfrac{3}{1\cdot4}+\dfrac{3}{4\cdot7}+...+\dfrac{3}{x\left(x+3\right)}=\dfrac{18}{19}\)

\(\Leftrightarrow1-\dfrac{1}{x+3}=\dfrac{18}{19}\)

=>x+3=19

hay x=16

Tìm x :

a) \(2.x.\frac{-3}{4}=-\frac{5}{12}\)

\(\Rightarrow2x=-\frac{5}{12}:-\frac{3}{4}\)

\(\Rightarrow2x=\frac{5}{9}\)

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

\(\Rightarrow x=\frac{5}{18}\)

Vậy : \(x=\frac{5}{18}\)

b) \(\frac{2}{3}+\frac{1}{3}.x=7\)

\(\Rightarrow\frac{1}{3}.x=7-\frac{2}{3}\)

\(\Rightarrow\frac{1}{3}.x=\frac{19}{3}\)

\(\Rightarrow x=\frac{19}{3}:\frac{1}{3}\)

\(\Rightarrow x=19\)

Vậy : \(x=19\)

c) \(\left(4.x+\frac{1}{8}\right)=\frac{3}{10}\)

\(\Rightarrow4.x=\frac{3}{10}-\frac{1}{8}\)

\(\Rightarrow4.x=\frac{7}{40}\)

\(\Rightarrow x=\frac{7}{40}:4\)

\(\Rightarrow x=\frac{7}{160}\)

Vậy : \(x=\frac{7}{160}\)

d) \(\frac{1}{3}.x-5=1\frac{1}{2}\)

\(\Rightarrow\frac{1}{3}.x-5=\frac{3}{2}\)

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

\(\Rightarrow\frac{1}{3}.x=\frac{13}{2}\)

\(\Rightarrow x=\frac{13}{2}:\frac{1}{3}\)

\(\Rightarrow x=\frac{39}{2}\)

Vậy : \(x=\frac{39}{2}\)

e) \(-\frac{2}{3}.x+\frac{1}{3}=-\frac{1}{2}\)

\(\Rightarrow-\frac{2}{3}.x=-\frac{1}{2}-\frac{1}{3}\)

\(\Rightarrow-\frac{2}{3}.x=-\frac{5}{6}\)

\(\Rightarrow x=-\frac{5}{6}:\left(-\frac{2}{3}\right)\)

\(\Rightarrow x=\frac{5}{4}\)

Vậy : \(x=\frac{5}{4}\)

a) \(\frac{9}{20}\)                                                   c) \(\frac{-55}{4}\)                                                                                                                                 

b) \(\frac{116}{75}\)                                                d) \(\frac{-76}{45}\)

đúng hết đấy nhé mình tính kĩ lắm ko sai đâu

       chúc may mắn

X : \(3\frac{1}{15}\)=\(1\frac{1}{2}\)

X : \(\frac{46}{15}\)=\(\frac{3}{2}\)

X =  \(\frac{3}{2}\)X \(\frac{46}{15}\)

X = \(\frac{23}{5}\)

#)Giải :

\(x\div3\frac{1}{5}=1\frac{1}{2}\)

\(\Leftrightarrow x\div\frac{16}{5}=\frac{3}{2}\)

\(\Leftrightarrow x=\frac{24}{5}\)hay \(4\frac{4}{5}\)

\(\frac{2}{3}x-\frac{1}{2}x=\frac{5}{12}\)

\(\Leftrightarrow\left(\frac{2}{3}-\frac{1}{2}\right)x=\frac{5}{12}\)

\(\Leftrightarrow\frac{1}{6}x=\frac{5}{12}\)

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

a) (\(6\frac{2}{7}.x+\frac{3}{7}\))=-1.\(\frac{11}{5}+\frac{3}{7}\)

(\(6\frac{2}{7}.x+\frac{3}{7}\))=\(\frac{-62}{35}\)

\(\frac{44}{7}.x\)=\(\frac{-62}{35}-\frac{3}{7}\)

\(\frac{44}{7}.x=\frac{-77}{35}\)

x=\(\frac{-77}{35}:\frac{44}{7}\)=\(\frac{539}{1540}\)

(6\(\frac27x\) + \(\frac37\)) : 2\(\frac15\) - \(\frac37\) = - 1

(\(\frac{44}{7}x\) + \(\frac37\)) : \(\frac{11}{5}\) = - 1 + \(\frac37\)

(\(\frac{44}{7}x+\) \(\frac37\)) : \(\frac{11}{5}\) = - \(\frac77+\frac37\)

\(\frac{44x+3}{7}\) : \(\frac{11}{5}\) = - \(\frac47\)

(44\(x\) + 3) : \(\frac{11}{5}\) = - 4

44\(x\) + 3 = - 4 x \(\frac{11}{5}\)

44\(x\) + 3 = - \(\frac{44}{5}\)

44\(x\) = - \(\frac{44}{5}\) - 3

44\(x\) = - \(\frac{59}{5}\)

\(x=-\frac{59}{5}:44\)

\(x\) = - \(\frac{59}{250}\)

Vậy \(x\) = - \(\frac{59}{250}\)

a) \(\frac{x-3}{3}-1=\frac{x}{-4}\)

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

\(\Leftrightarrow\frac{x-6}{3}=\frac{x}{-4}\)

\(\Leftrightarrow-4\left(x-6\right)=3x\)

\(\Leftrightarrow-4x+24=3x\)

\(\Leftrightarrow24=3x+4x\)

\(\Leftrightarrow7x=24\)

\(\Leftrightarrow x=\frac{24}{7}\)

b) \(\frac{5}{8}-\left(x-\frac{1}{2}\right)=\frac{-3}{4}\)

\(\Leftrightarrow\frac{5}{8}-x+\frac{1}{2}=\frac{-3}{4}\)

\(\Leftrightarrow\frac{5}{8}+\frac{4}{8}-x=\frac{-3}{4}\)

\(\Leftrightarrow\frac{9}{8}-x=\frac{-3}{4}\)

\(\Leftrightarrow x=\frac{9}{8}+\frac{3}{4}\)

\(\Leftrightarrow x=\frac{15}{8}\)

|\(\frac32x\) + \(\frac12\)| = |4\(x\) - 1|

\(\left[\begin{array}{l}\frac32x+\frac12=-4x+1\\ \frac32x+\frac12=4x-1\end{array}\right.\)

\(\left[\begin{array}{l}\frac32x+4x=1-\frac12\\ \frac32x-4x=-1-\frac12\end{array}\right.\)

\(\left[\begin{array}{l}\frac{11}{2}x=\frac12\\ -\frac52x=-\frac32\end{array}\right.\)

\(\left[\begin{array}{l}x=\frac12:\frac{11}{2}\\ x=-\frac32:\frac{-5}{2}\end{array}\right.\)

\(\left[\begin{array}{l}x=\frac12\times\frac{2}{11}\\ x=-\frac32\times\frac{-2}{5}\end{array}\right.\)

\(\left[\begin{array}{l}x=\frac{1}{11}\\ x=\frac35\end{array}\right.\)

Vậy \(x\in\) {\(\frac{1}{11};\frac35\)}

|\(\frac54x\) - \(\frac72\)| - |\(\frac58x\) + \(\frac35\)| = 0

|\(\frac54x\) - \(\frac72\)| = |\(\frac58x\) + \(\frac35\)|

\(\left[\begin{array}{l}\frac54x-\frac72=-\frac58x-\frac35\\ \frac54x-\frac72=\frac58x+\frac35\end{array}\right.\)

\(\left[\begin{array}{l}\frac54x+\frac58x=\frac72-\frac35\\ \frac54x-\frac58x=\frac72+\frac35\end{array}\right.\)

\(\left[\begin{array}{l}\frac{15}{8}x=\frac{29}{20}\\ \frac58x=\frac{41}{10}\end{array}\right.\)

\(\left[\begin{array}{l}x=\frac{29}{10}:\frac{15}{8}\\ x=\frac{41}{10}:\frac58\end{array}\right.\)

\(\left[\begin{array}{l}x=\frac{116}{75}\\ x=\frac{164}{25}\end{array}\right.\)

Vậy \(x\in\) {\(\frac{116}{75}\); \(\frac{164}{25}\)}

\(a.-1,52+\frac{2}{47}-x=3.\)

\(\Leftrightarrow\frac{2}{47}-x=4,52\)

\(\Leftrightarrow x=\frac{2}{47}-4,52\)

\(\Leftrightarrow x=-\frac{5261}{1175}\)

\(b.x+3,5-\frac{4}{7}=\frac{3}{2}-1\frac{3}{5}\)

\(\Leftrightarrow x=\frac{3}{2}-\frac{8}{5}-\frac{7}{2}+\frac{4}{7}\)

\(\Leftrightarrow x=-\frac{106}{35}\)

\(c.\left(x:2\frac{1}{8}\right).\frac{1}{6}=-\frac{3}{8}.\left(\frac{1}{2}-1\frac{3}{5}\right)\)

\(\Leftrightarrow\left(x:\frac{17}{8}\right).\frac{1}{6}=-\frac{3}{16}+\frac{3}{5}\)

\(\Leftrightarrow\left(x:\frac{17}{8}\right).\frac{1}{6}=\frac{33}{80}\)

\(\Leftrightarrow x:\frac{17}{8}=\frac{99}{40}\)

\(\Leftrightarrow x=\frac{99}{40}.\frac{17}{8}\)

\(\Leftrightarrow x=\frac{1683}{320}\)