\(a,2x+\dfrac{5}{2}=-\dfrac{3}{5}\)

\(2x=-\dfrac{3}{5}-\dfrac{5}{2}\)

\(2x=-\dfrac{31}{10}\)

\(x=-\dfrac{31}{10}:2\)

\(x=-\dfrac{31}{20}\)

\(b,\dfrac{1}{2}:x-\dfrac{5}{6}=-\dfrac{2}{3}\)

\(\dfrac{1}{2}:x=-\dfrac{2}{3}+\dfrac{5}{6}\)

\(\dfrac{1}{2}:x=\dfrac{1}{6}\)

\(x=\dfrac{1}{2}:\dfrac{1}{6}\)

\(x=3\)

\(c,\left(312-x\right):12,6=24,5\)

\(312-x=24,5\times12,6\)

\(312-x=308,7\)

\(x=312-308,7\)

`x=3,3`

a: =>2x=-3/5-5/2=-6/10-25/10=-31/10

=>x=-31/20

b: =>1/2:x=-2/3+5/6=5/6-4/6=1/6

=>x=1/2:1/6=3

c: =>312-x=308,7

=>x=3,3

a: \(\left(x-4\right)^2-\left(x-3\right)\left(x+3\right)=5\)

\(\Leftrightarrow x^2-8x+16-x^2+9=5\)

\(\Leftrightarrow-8x=-20\)

hay \(x=\dfrac{5}{2}\)

a: x=2/5*15=6

b: =>x-7=15

=>x=22

c: =>3/4:x+1/2*4=4

=>3/4:x=4-2=2

=>x=3/8

a: \(\Leftrightarrow\left[{}\begin{matrix}x-\dfrac{3}{4}=\dfrac{1}{5}\\x-\dfrac{3}{4}=-\dfrac{1}{5}\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{19}{20}\\x=\dfrac{11}{20}\end{matrix}\right.\)

\(a,\left|x-\dfrac{3}{4}\right|=\dfrac{1}{5}\)

\(\Leftrightarrow\left[{}\begin{matrix}x-\dfrac{3}{4}=\dfrac{1}{5}\\x-\dfrac{3}{4}=\dfrac{-1}{5}\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{19}{20}\\x=\dfrac{11}{20}\end{matrix}\right.\)

\(b,\dfrac{-1}{3}+\left|x\right|=0,5\)

\(\Leftrightarrow\left|x\right|=\dfrac{5}{6}\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{5}{6}\\x=\dfrac{-5}{6}\end{matrix}\right.\)

tìm x

a.9/25-12/25:x=1/5

12/25:x=9/25 - 1/5

12/25:x=4/25

x=12/25 : 4/25

x=1/3

b.8/17*x+2/9=10/27

8/17*x=10/27 - 2/9

8/17*x=4/27

x=4/27 : 8/17

x=17/45

a: =>12/25:x=9/25-1/5=4/25

=>x=3

b: =>8/17x=10/27-2/9=10/27-6/27=4/27

hay x=17/54

a: x=5:(-1/2)=-10

b: x=8/3+1/9=25/9

c: =>x+5/6=11/21

=>x=-13/42

d: =>7/4x-5=-10/3

=>7/4x=5/3

=>x=20/21

e: =>10/3-3/4:x=-1/6

=>3/4:x=10/3+1/6=21/6=7/2

=>x=3/4:7/2=3/4*2/7=6/28=3/14

g: =>3/(x+5)=3/20

=>x+5=20

=>x=15

h: =>1-1/2+1/2-1/3+...+1/x-1/x+1=49/50

=>1-1/x+1=49/50

=>x+1=50

=>x=49

A)    \(x-\dfrac{2}{3}=\dfrac{4}{5}\\ x=\dfrac{4}{5}+\dfrac{2}{3}\)

           \(x=\dfrac{22}{15}\)

b)\(\dfrac{7}{9}-x=\dfrac{1}{3}\\ x=\dfrac{7}{9}-\dfrac{1}{3}\\ x=\dfrac{4}{9}\)

C)\(x:\dfrac{2}{3}=\dfrac{9}{8}\\ x=\dfrac{9}{8}x\dfrac{2}{3}\\ x=\dfrac{3}{4}\)