9/8 + 3/8x = 0,125 = 1/8

3/8x = 1/8 - 9/8 = -1

=> x = -1 : 3/8 = -8/3        

\(\left(0,125+40\%-\dfrac{3}{40}\right):\left[11\dfrac{3}{7}+8\dfrac{1}{2}-\left(\dfrac{13}{12}-5\dfrac{4}{7}\right)\right]\)

\(=\left(\dfrac{1}{8}+\dfrac{2}{5}-\dfrac{3}{40}\right):\left[\dfrac{80}{7}+\dfrac{17}{2}-\left(\dfrac{13}{12}-\dfrac{39}{7}\right)\right]\)

\(=\dfrac{9}{20}:\dfrac{293}{12}\)

\(=\dfrac{27}{1465}\)

\(=1132-137=995\)

\(\frac{2}{3}\cdot x-0,125=\frac{15}{8}\)

\(\frac{2}{3}\cdot x=\frac{15}{8}+0,125=\frac{15}{8}+\frac{1}{8}=2\)

\(x=2:\frac{2}{3}=2\cdot\frac{3}{2}=3\)

Vậy x=3

2/3.x - 0,125 = 15/8

    2/3.x - 1/8 = 15/8

            2/3.x = 15/8 +1/8

            2/3.x = 2  

                 x = 2:2/3

                 x = 3    

3/ 4x=1 <=>x=1/4

4/7x=9/8-0,125 <=>7x=1<=>x=1/7

3/4x=1

<=>x=4/3

4/7x=9/8-0,125

<=>4/7x=9/8-1/8=8/8=1

<=>x=7/4

a)\(\frac{3}{4}\cdot x=1\)

   \(x=1:\frac{3}{4}=\frac{4}{3}\)

b) \(2\frac{4}{7}\cdot x=\frac{9}{8}-0,125\)

   \(\frac{18}{7}\cdot x=\frac{9}{8}-\frac{1}{8}\)

   \(\frac{18}{7}\cdot x=1\)

    \(x=1:\frac{18}{7}=\frac{7}{18}\)

a/

   3/4 . x = 1

  => x= 1: 3/4 = 4/3

b/

       4/7 .x = 9/8 -0,125 = 9/8 -1/8 = 1

   => x= 1 : 4/7 = 7/4

a/ 3/4x=1

x=1:3/4

x=4/3

b/ 4/7x=9/8-0,125

4/7x=1

x=1:4/7

x=7/4

a, \(\left(\dfrac{7}{2}-2x\right).\dfrac{10}{3}=\dfrac{22}{3}\Leftrightarrow\dfrac{7}{2}-2x=\dfrac{22}{10}=\dfrac{11}{5}\)

\(\Leftrightarrow2x=\dfrac{13}{10}\Leftrightarrow x=\dfrac{13}{20}\)

b, \(\dfrac{4x}{9}=\dfrac{9}{8}-\dfrac{125}{1000}=1\Leftrightarrow x=\dfrac{9}{4}\)

c, \(-\dfrac{x}{21}=\dfrac{60}{21}\Rightarrow x=-60\)

Lời giải:
a)

\(\frac{3}{4}x=1\)

\(x=1:\frac{3}{4}=1.\frac{4}{3}=\frac{4}{3}\)

b)

\(\frac{4}{7}x=\frac{9}{8}-0,125\)

\(\frac{4}{7}x=1\)

\(x=1:\frac{4}{7}\)

\(x=\frac{7}{4}\)

a.\(\frac{61}{210}\)

b.\(\frac{7}{5}\)