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15 tháng 10 2017

\(\dfrac{15}{4}-2,5:\left|\dfrac{3}{4}.x+\dfrac{1}{2}\right|=3\)

\(\Rightarrow2,5:\left|\dfrac{3}{4}.x+\dfrac{1}{2}\right|=\dfrac{15}{4}-3\)

\(\Rightarrow2,5:\left|\dfrac{3}{4}.x+\dfrac{1}{2}\right|=\dfrac{3}{4}\)

\(\Rightarrow\left|\dfrac{3}{4}x+\dfrac{1}{2}\right|=2,5:\dfrac{3}{4}\)

\(\Rightarrow\left|\dfrac{3}{4}x+\dfrac{1}{2}\right|=\dfrac{10}{3}\)

\(\Rightarrow\left[{}\begin{matrix}\dfrac{3}{4}x+\dfrac{1}{2}=\dfrac{10}{3}\\\dfrac{3}{4}x+\dfrac{1}{2}=-\dfrac{10}{3}\end{matrix}\right.\) \(\Rightarrow\left[{}\begin{matrix}\dfrac{3}{4}x=\dfrac{17}{6}\\\dfrac{3}{4}x=\dfrac{-23}{6}\end{matrix}\right.\) \(\Rightarrow\left[{}\begin{matrix}x=\dfrac{34}{9}\\x=\dfrac{-46}{9}\end{matrix}\right.\)

Vậy............

10 tháng 4 2018

a, x= 2 x 2,5x 3,1

    x=15,5

b, x= 32,8:1,2;8,2

    x=10/3

c, x=(3/4x15/16 +1) :3

    x=109/192

d, x= 2,x13,7:2,5-3,7

    x=10

k cho mình nha!

10 tháng 4 2018

a, x= 15.5

b x= 10/3

c x= 0.6

d x= 10

1: =>x:7/3=-3/2

hay \(x=-\dfrac{3}{2}\cdot\dfrac{7}{3}=-\dfrac{7}{2}\)

2: \(x=\dfrac{11}{15}:\dfrac{2}{5}=\dfrac{11}{15}\cdot\dfrac{5}{2}=\dfrac{55}{30}=\dfrac{11}{6}\)

3: \(x=-\dfrac{6}{5}:\dfrac{3}{10}=\dfrac{-6}{5}\cdot\dfrac{10}{3}=\dfrac{-60}{15}=-4\)

4: \(x=\dfrac{1}{3}+\dfrac{3}{20}=\dfrac{20+9}{60}=\dfrac{29}{60}\)

6: \(\Leftrightarrow x\cdot\dfrac{13}{20}=\dfrac{5}{4}\)

hay \(x=\dfrac{5}{4}:\dfrac{13}{20}=\dfrac{5}{4}\cdot\dfrac{20}{13}=\dfrac{100}{52}=\dfrac{25}{13}\)

21 tháng 3 2022

\(a,-\dfrac{13}{20}+x=\dfrac{-11}{15}\\ \Rightarrow x=\dfrac{-11}{15}+\dfrac{13}{20}\\ \Rightarrow x=-\dfrac{1}{12}\\ b,\left(x-3,5\right):3\dfrac{1}{2}-2,5=-1\dfrac{3}{4}\\ \Rightarrow\left(x-\dfrac{7}{2}\right):\dfrac{7}{2}-\dfrac{5}{2}=\dfrac{-7}{4}\\ \Rightarrow\left(x-\dfrac{7}{2}\right):\dfrac{7}{2}=\dfrac{3}{4}\\ \Rightarrow x-\dfrac{7}{2}=\dfrac{21}{8}\\ \Rightarrow x=\dfrac{49}{8}\)

a) Ta có: \(\dfrac{x}{-15}=\dfrac{-60}{x}\)

\(\Leftrightarrow x^2=\left(-15\right)\cdot\left(-60\right)=900\)

hay \(x\in\left\{30;-30\right\}\)

Vậy: \(x\in\left\{30;-30\right\}\)

b) Ta có: \(\left|x\right|+0.573=2\)

\(\Leftrightarrow\left|x\right|=1.427\)

hay \(x\in\left\{1.427;-1.427\right\}\)

Vậy: \(x\in\left\{1.427;-1.427\right\}\)

c) Ta có: \(\left|x+\dfrac{1}{3}\right|-4=-1\)

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

\(\Leftrightarrow\left[{}\begin{matrix}x+\dfrac{1}{3}=3\\x+\dfrac{1}{3}=-3\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{8}{3}\\x=-\dfrac{10}{3}\end{matrix}\right.\)

Vậy: \(x\in\left\{\dfrac{8}{3};-\dfrac{10}{3}\right\}\)

d) Ta có: \(0.01:2.5=\left(0.75x\right):0.75\)

\(\Leftrightarrow\dfrac{0.75\cdot x}{0.75}=\dfrac{0.01}{2.5}\)

\(\Leftrightarrow x=\dfrac{1}{250}\)

Vậy: \(x=\dfrac{1}{250}\)

4 tháng 5 2018

a) 3x-1=16*3/4*15

3x=48/60+60/60

3x=108/60

x=0,6

b) 2,5*(x+3,7)=34,25

x+3,7=13,7

x=10

16 tháng 4 2021

\(a.32,5-3\cdot0,87=32,5-2,61=29,89\)

\(8,5\cdot\left(1\dfrac{1}{2}+\dfrac{4}{4}\right):5=8,5\cdot\left(\dfrac{3}{2}+\dfrac{4}{4}\right):5\\ =8,5\cdot\left(\dfrac{6}{4}+\dfrac{4}{4}\right):5\\ =8,5\cdot\dfrac{10}{4}:5\\ =\dfrac{85}{4}:5\\ =\dfrac{17}{4}\)

\(b.30,96-6,45+14,4:3=30,96-6,45+4,8\\ =29,31\)

\(\dfrac{2}{5}\cdot\left(\dfrac{4}{5}-\dfrac{1}{2}\right)=\dfrac{2}{5}\cdot\left(\dfrac{8}{10}-\dfrac{5}{10}\right)\\ =\dfrac{2}{5}\cdot\dfrac{3}{10}=\dfrac{3}{25}\)

bài 2

\(a.2,5\cdot12,5\cdot8\cdot0,4=\left(2,5\cdot0,4\right)\left(12,5\cdot8\right)\\ =1\cdot100=100\)

b,\(\dfrac{12}{15}\cdot\dfrac{5}{6}\cdot\dfrac{3}{20}\cdot\dfrac{32}{5}=\dfrac{12\cdot5\cdot3\cdot32}{15\cdot6\cdot20\cdot5}\\ =\dfrac{3\cdot4\cdot5\cdot3\cdot4\cdot8}{3\cdot5\cdot2\cdot3\cdot5\cdot4\cdot5}=\dfrac{16}{25}\)

 

Bài 1: 

a) \(32.5-3\cdot0.87=32.5-2.61=29.89\)

\(8.5\cdot\left(1\dfrac{1}{2}+\dfrac{4}{4}\right):5=8.5\cdot\dfrac{5}{2}:5=\dfrac{17}{2}\cdot\dfrac{5}{2}:5=\dfrac{85}{4}\cdot\dfrac{1}{5}=\dfrac{17}{4}\)

23 tháng 4 2023

a\()\)1/2-1/2:x=3/4

1/2:x=3/4+1/2

1/2:x=5/4

x=5/4*1/2

x=5/8

GH
5 tháng 5 2023