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7 tháng 4 2017

Ta có :

\(0,5\times x-\dfrac{2}{3}\times x=\dfrac{5}{12}\)

\(\Rightarrow\dfrac{1}{2}\times x-\dfrac{2}{3}\times x=\dfrac{5}{12}\)

\(\Rightarrow x\times\left(\dfrac{1}{2}-\dfrac{2}{3}\right)=\dfrac{5}{12}\)

\(\Rightarrow x\times\dfrac{-1}{6}=\dfrac{5}{12}\)

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

Vậy \(x=\dfrac{-5}{2}\) là giá trj cần tìm

~ Chúc bn học tốt ~

16 tháng 4 2017

\(\dfrac{-5}{2}\)

a: =>3/2x=64/15

=>x=128/45

b: =>-1/6x=7/12

=>x=-7/2

c: =>11/2*x=1/2

=>x=1/2:11/2=1/11

29 tháng 3 2017

Tìm x:

a, x+30%=-1,3

<=> x+0,3=-1,3

<=> x=-1,3-0,3

<=> x=-1,6

Vậy x=-1,6

b, 0,5x-\(\dfrac{2}{3}x\) =\(\dfrac{7}{12}\)

<=>\(\dfrac{-1}{6}x\)=\(\dfrac{7}{12}\)

<=> x=\(\dfrac{-7}{2}\)

Vậy x=\(\dfrac{-7}{2}\)

=>1/2:(0,5x-1,5)=0,2-0,35=-0,15=-3/20

=>0,5x-1,5=1/2:(-3/20)=-1/2*20/3=-10/3

=>0,5x=-10/3+3/2=-11/6

=>x=-11/3

6 tháng 4 2017

\(0,5x-\dfrac{2}{3}x=\dfrac{5}{12}\)

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

\(\Rightarrow x\left(\dfrac{1}{2}-\dfrac{2}{3}\right)=\dfrac{5}{12}\)

\(\Rightarrow x\dfrac{-1}{6}=\dfrac{5}{12}\)

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

Vậy .......

6 tháng 4 2017

Ta có: 0,5x-\(\dfrac{2}{3}\)x =\(\dfrac{5}{12}\)

\(\Leftrightarrow\) \(x\left(0,5-\dfrac{2}{3}\right)=\dfrac{5}{12}\)

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

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

Sao dốt thế

12 tháng 9 2017

a.\(\dfrac{-4}{5}-\left(\dfrac{2}{3}x+1\dfrac{1}{4}\right)=\dfrac{2}{7}\)

\(\left(\dfrac{2}{3}x+1\dfrac{1}{4}\right)=\dfrac{-4}{5}-\dfrac{2}{7}=\dfrac{-38}{35}\)

\(\dfrac{2}{3}x=\dfrac{-38}{35}-1\dfrac{1}{4}\)

\(\dfrac{2}{3}x=\dfrac{-327}{140}\Rightarrow x=\dfrac{-327}{140}:\dfrac{2}{3}=\dfrac{-981}{280}\)

Vậy \(x=\dfrac{-981}{280}\)

b. \(\dfrac{5}{6}+\left(\dfrac{3}{4}-\dfrac{1}{2}:x\right)=\dfrac{-2}{3}\)

\(\left(\dfrac{3}{4}-\dfrac{1}{2}:x\right)=\dfrac{-2}{3}-\dfrac{5}{6}=\dfrac{-3}{2}\)

\(\dfrac{1}{2}:x=\dfrac{3}{4}-\dfrac{-3}{2}\)

\(\dfrac{1}{2}:x=\dfrac{9}{4}\Rightarrow x=\dfrac{1}{2}:\dfrac{9}{4}=\dfrac{2}{9}\)

Vậy \(x=\dfrac{2}{9}\)

c. \(\left(\dfrac{4}{5}x-1\dfrac{1}{3}\right):\dfrac{3}{4}=0,7\)

\(\left(\dfrac{4}{5}x-1\dfrac{1}{3}\right)=0,7.\dfrac{3}{4}=\dfrac{21}{40}\)

\(\dfrac{4}{5}x=\dfrac{21}{40}+1\dfrac{1}{3}=\dfrac{223}{120}\)

\(\Rightarrow x=\dfrac{223}{120}:\dfrac{4}{5}=\dfrac{223}{96}\)

Vậy \(x=\dfrac{223}{96}\)

d. \(\dfrac{5}{6}-\dfrac{3}{4}x=1\dfrac{1}{3}+0,5x\)

\(0,5x+\dfrac{3}{4}x=\dfrac{5}{6}-1\dfrac{1}{3}\)

\(\dfrac{5}{4}x=\dfrac{-1}{2}\Rightarrow x=\dfrac{-1}{2}:\dfrac{5}{4}=\dfrac{-2}{5}\)

Vậy \(x=\dfrac{-2}{5}\)

a: =>2480-1570+(205-x)=1010

=>205-x=100

hay x=105

b: \(\Leftrightarrow x\cdot\dfrac{1}{2}\cdot\dfrac{13}{12}=\dfrac{7}{60}\cdot3\cdot4=\dfrac{7}{5}\)

=>x=168/65

2 tháng 4 2017

a) \(0,5x-\dfrac{2}{3}x=\dfrac{7}{12}\)

\(\dfrac{1}{2}x-\dfrac{2}{3}x=\dfrac{7}{12}\)

\(\left(\dfrac{1}{2}-\dfrac{2}{3}\right)x=\dfrac{7}{12}\)

\(\dfrac{-1}{6}x=\dfrac{7}{12}\)

\(x=\dfrac{7}{12}:\dfrac{-1}{6}\)

\(x=\dfrac{-7}{2}\)

b) \(x:4\dfrac{1}{3}=-2,5\)

\(x:\dfrac{13}{3}=\dfrac{-5}{2}\)

\(x=\dfrac{13}{3}.\dfrac{-5}{2}\)

\(x=\dfrac{-65}{6}\)

c) \(5,5x=\dfrac{13}{15}\)

\(\dfrac{11}{2}x=\dfrac{13}{15}\)

\(x=\dfrac{13}{15}:\dfrac{11}{2}\)

\(x=\dfrac{26}{165}\)

d) \(\left(\dfrac{3x}{7}+1\right):\left(-4\right)=\dfrac{-1}{28}\)

\(\left(\dfrac{3x}{7}+1\right)=\dfrac{-1}{28}.\left(-4\right)\)

\(\dfrac{3x}{7}+1=\dfrac{1}{7}\)

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

\(\dfrac{3x}{7}=\dfrac{-6}{7}\)

\(\Rightarrow3x=-6\\ x=\left(-6\right):3\\ x=-2\)

2 tháng 4 2017

câu d mình nhầm bạn nha

d)\(\left(\dfrac{3x}{7}+1\right):\left(-4\right)=\dfrac{-1}{28}\)

\(\dfrac{3x}{7}+1=\dfrac{-1}{28}.\left(-4\right)\)

\(\left(\dfrac{3x}{7}+1\right)=\dfrac{1}{7}\)

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

\(\dfrac{3x}{7}=\dfrac{-6}{7}\)

Ta có : 3x =-6

x = -6:3

x=-2

27 tháng 7 2021

\(\Leftrightarrow\dfrac{1}{2}x+\dfrac{2}{3}x-x=-4\Leftrightarrow\dfrac{3x+4x-6x}{6}=-\dfrac{24}{6}\)

\(\Rightarrow x=-24\)

27 tháng 7 2021

b) \(x.\left(\dfrac{1}{2}+\dfrac{2}{3}-1\right)=-4\)

\(x.\dfrac{-1}{6}=-4\)

\(x=-4:\dfrac{-1}{6}\)

\(x=-24\)

4 tháng 3 2022

\(a,\dfrac{3}{4}x-\dfrac{7}{12}=\dfrac{5}{6}-\dfrac{2}{3}\\ \Rightarrow\dfrac{3}{4}x-\dfrac{7}{12}=\dfrac{1}{6}\\ \Rightarrow\dfrac{3}{4}x=\dfrac{1}{6}+\dfrac{7}{12}\\ \Rightarrow\dfrac{3}{4}x=\dfrac{3}{4}\\ \Rightarrow x=\dfrac{3}{4}:\dfrac{3}{4}\\ \Rightarrow x=1\\ b,\dfrac{-5}{x}=\dfrac{20}{28}\\ \Rightarrow\dfrac{-5}{x}=\dfrac{5}{7}\\ \Rightarrow\dfrac{-5}{x}=\dfrac{-5}{-7}\\ \Rightarrow x=-7\\ c,2\dfrac{1}{3}:x=7\\ \Rightarrow\dfrac{7}{3}:x=7\\ \Rightarrow x=\dfrac{7}{3}:7\\ \Rightarrow x=\dfrac{1}{3}\)

\(d,\dfrac{-105}{12}< x< \dfrac{20}{7}\Rightarrow x\in\left\{-8;-7;...;2\right\}\)

a: \(\Leftrightarrow x\cdot\dfrac{3}{4}=\dfrac{3}{4}\)

hay x=1

b: \(\Leftrightarrow x=\dfrac{-28\cdot5}{20}=-7\)

c: \(\Leftrightarrow x=\dfrac{7}{3}:7=\dfrac{1}{3}\)

d: \(\Leftrightarrow-8< x< 3\)

hay \(x\in\left\{-7;-6;-5;-4;-3;-2;-1;0;1;2\right\}\)