b: \(\dfrac{5}{7}-\dfrac{2}{3}\cdot x=\dfrac{4}{5}\)

=>\(\dfrac{2}{3}x=\dfrac{5}{7}-\dfrac{4}{5}=\dfrac{25-28}{35}=\dfrac{-3}{35}\)

=>\(x=-\dfrac{3}{35}:\dfrac{2}{3}=\dfrac{-3}{35}\cdot\dfrac{3}{2}=-\dfrac{9}{70}\)
c: \(\dfrac{1}{2}x+\dfrac{3}{5}x=-\dfrac{2}{3}\)

=>\(x\left(\dfrac{1}{2}+\dfrac{3}{5}\right)=-\dfrac{2}{3}\)

=>\(x\cdot\dfrac{5+6}{10}=\dfrac{-2}{3}\)

=>\(x\cdot\dfrac{11}{10}=-\dfrac{2}{3}\)

=>\(x=-\dfrac{2}{3}:\dfrac{11}{10}=-\dfrac{2}{3}\cdot\dfrac{10}{11}=\dfrac{-20}{33}\)

d: \(\dfrac{4}{7}\cdot x-x=-\dfrac{9}{14}\)

=>\(\dfrac{-3}{7}\cdot x=\dfrac{-9}{14}\)

=>\(\dfrac{3}{7}\cdot x=\dfrac{9}{14}\)

=>\(x=\dfrac{9}{14}:\dfrac{3}{7}=\dfrac{9}{14}\cdot\dfrac{7}{3}=\dfrac{3}{2}\)

a: x=2/3-4/5=10/15-12/15=-2/15

b: 1/2-x=7/12

=>x=1/2-7/12=-1/12

c: =>7/2:x=-7/2

=>x=-1

d: =>1/6x=3/8-5/2=3/8-20/8=-17/8

=>x=-17/8*6=-102/8=-51/4

e: =>1,5x=-1,5

=>x=-1

a.(x+2)+(x+5)+(x+8)+(x+11)+(x+14)=75

=>(x+x+x+x+x)+(2+5+8+11+14)=75

=>Xx5+40=75

=>Xx5=75-40

=>Xx5=35

=>x=35:5

=>x=7

\(a,x-\dfrac{5}{7}=\dfrac{3}{5}\times\dfrac{1}{2}\)

\(x-\dfrac{5}{7}=\dfrac{3}{10}\)

\(x=\dfrac{3}{10}+\dfrac{5}{7}\)

\(x=\dfrac{21}{70}+\dfrac{50}{70}\)

\(x=\dfrac{71}{70}\)

\(Vayx=\dfrac{71}{70}\)

\(b,x\times\dfrac{2}{3}=\dfrac{5}{8}+\dfrac{3}{4}\)

\(x\times\dfrac{2}{3}=\dfrac{5}{8}+\dfrac{6}{8}\)

\(x\times\dfrac{2}{3}=\dfrac{11}{8}\)

\(x=\dfrac{11}{8}:\dfrac{2}{3}\)

\(x=\dfrac{11}{8}\times\dfrac{3}{2}\)

\(x=\dfrac{33}{16}\)

\(Vayx=\dfrac{33}{16}\)

\(a;343-4\times\left(x+1\right)=143\)

\(4\times\left(x+1\right)=343-143\)

\(4\times\left(x+1\right)=200\)

\(x+1=200:4\)

\(x+1=50\)

\(x=50-1=49\)

Mấy câu hỏi trẻ trâu thì tự tính nhé

\(\frac{1}{5.8}+\frac{1}{8.11}+...+\frac{1}{x.\left(x+3\right)}=\frac{101}{1540}\)

\(\Leftrightarrow\frac{1}{3}.\left(\frac{3}{5.8}+\frac{3}{8.11}+...+\frac{3}{x.\left(x+3\right)}\right)=\frac{101}{1540}\)

\(\Leftrightarrow\frac{1}{3}\left(\frac{1}{5}-\frac{1}{8}+\frac{1}{8}-\frac{1}{11}+...+\frac{1}{x}-\frac{1}{x+3}\right)=\frac{101}{1540}\)

\(\Leftrightarrow\frac{1}{3}.\left(\frac{1}{5}-\frac{1}{x+3}\right)=\frac{101}{1540}\)

\(\Leftrightarrow\frac{1}{5}-\frac{1}{x+3}=\frac{303}{1540}\)

\(\Leftrightarrow\frac{1}{x+3}=\frac{1}{308}\)

\(\Leftrightarrow x+3=308\)

\(\Leftrightarrow x=305\)

Vậy x=305

\(131+\left(26-3\times x\right):5=135\)

\(\left(26-3\times x\right):5=135-131\)

\(\left(26-3\times x\right):5=4\)

\(26-3\times x=4\times5\)

\(26-3\times x=20\)

\(3\times x=26-20\)

\(3\times x=6\)

\(x=6:3=2\)

    (x+1)+(x+4)+(x+7)+...+(x+94)=1840

=>(x+x+x+....+x)+(1+2+3+...+94)=1840

       32 S/H x

=>32x+1520=1840

=>32x  =1840-1520 = 320

=> x= 320:32 =10

Vậy x=10.    bấm đúng cho mk nhé!

a: =>x*7/4+3/2=-4/5

=>x*7/4=-4/5-3/2=-8/10-15/10=-23/10

=>x=-23/10:7/4=-23/10*4/7=-92/70=-46/35

b: =>x*9/20=1/7+1/8=15/56

=>x=15/56:9/20=15/56*20/9=25/42

c: |x|=3,5

=>x=3,5 hoặc x=-3,5

d: |x|=-2,7

=>x thuộc rỗng

e: =>|x-1|=3-0,73=2,27

=>x-1=2,27 hoặc x-1=-2,27

=>x=-1,27 hoặc x=3,27

f: \(\Leftrightarrow7\cdot11x+11=0\)

=>77x=-11

=>x=-1/7

l: =>|x+3/4|=-2+5=3

=>x+3/4=3 hoặc x+3/4=-3

=>x=-15/4 hoặc x=9/4

\(a.\dfrac{1}{2}:3+x=\dfrac{14}{5}\)

\(\dfrac{1}{6}+x=\dfrac{14}{5}\)

\(=>x=\dfrac{79}{30}\)

\(b.\dfrac{8}{5}:x:\dfrac{7}{4}=\dfrac{11}{6}\)

\(\left(\dfrac{8}{5}\cdot\dfrac{4}{7}\right):x=\dfrac{11}{6}\)

\(\dfrac{32}{35}:x=\dfrac{11}{6}\)

\(x=\dfrac{192}{385}\)

\(c.\dfrac{24}{10}+x:\dfrac{3}{4}=\dfrac{11}{3}\)

\(x:\dfrac{3}{4}=\dfrac{11}{3}-\dfrac{24}{10}\)

\(x:\dfrac{3}{4}=\dfrac{38}{30}\)

\(=>x=\dfrac{19}{20}\)

\(a,\dfrac{1}{2}:3+x=\dfrac{14}{5}\\ \Leftrightarrow x+\dfrac{1}{6}=\dfrac{14}{5}\\ \Leftrightarrow x=\dfrac{79}{30}\\ b,\dfrac{8}{5}:x:\dfrac{7}{4}=\dfrac{11}{6}\\ \Leftrightarrow x=\dfrac{192}{385}\\ c,\dfrac{24}{10}+x:\dfrac{3}{4}=\dfrac{11}{3}\\ \Leftrightarrow\dfrac{4}{3}x=\dfrac{19}{15}\\ \Leftrightarrow x=\dfrac{19}{20}\)

a   1/6+x=14/5

     x=14/5-1/6

     x= 79/30

b    8/5:x=11/6*7/4

     8/5:x=77/24

     x=77/24:8/5

     x=385/192

c  x:3/4=11/3-24/10

  x:3/4=19/5

  x=19/5*3/4

  x=57/20