\(0,28-0,3:\left(50\%.x-1\dfrac{1}{3}\right)=-1\dfrac{2}{3}\)
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18 tháng 10 2017

Giải:

\(0,28-0,3:\left(50\%x-1\dfrac{1}{3}\right)=-1\dfrac{2}{3}\)

\(\Leftrightarrow\dfrac{7}{25}-\dfrac{3}{10}:\left(\dfrac{1}{2}x-\dfrac{4}{3}\right)=-\dfrac{5}{3}\)

\(\Leftrightarrow\dfrac{3}{10}:\left(\dfrac{1}{2}x-\dfrac{4}{3}\right)=\dfrac{7}{25}-\left(-\dfrac{5}{3}\right)\)

\(\Leftrightarrow\dfrac{3}{10}:\left(\dfrac{1}{2}x-\dfrac{4}{3}\right)=\dfrac{146}{75}\)

\(\Leftrightarrow\dfrac{1}{2}x-\dfrac{4}{3}=\dfrac{3}{10}:\dfrac{146}{75}\)

\(\Leftrightarrow\dfrac{1}{2}x-\dfrac{4}{3}=\dfrac{45}{292}\)

\(\Leftrightarrow\dfrac{1}{2}x=\dfrac{45}{292}-\dfrac{4}{3}\)

\(\Leftrightarrow\dfrac{1}{2}x=-\dfrac{1033}{876}\)

\(\Leftrightarrow x=-\dfrac{1033}{876}:\dfrac{1}{2}\)

\(\Leftrightarrow x=-\dfrac{1033}{438}\)

Vậy \(x=-\dfrac{1033}{438}\).

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18 tháng 10 2017

\(\dfrac{1}{3}-\left(1\dfrac{1}{2}-x\right)=0,3\\ \dfrac{1}{3}-\left(\dfrac{3}{2}-x\right)=\dfrac{3}{10}\\ \dfrac{3}{2}-x=\dfrac{1}{3}-\dfrac{3}{10}\\ \dfrac{3}{2}-x=\dfrac{1}{30}\\ x=\dfrac{3}{2}-\dfrac{1}{30}=\dfrac{44}{30}\)

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

\(\Leftrightarrow\left(\dfrac{1}{2}x-\dfrac{1}{3}\right)^2=\dfrac{1}{4}\)

\(\Leftrightarrow\left[{}\begin{matrix}\dfrac{1}{2}x-\dfrac{1}{3}=\dfrac{1}{2}\\\dfrac{1}{2}x-\dfrac{1}{3}=-\dfrac{1}{2}\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{5}{3}\\x=-\dfrac{1}{3}\end{matrix}\right.\)

18 tháng 10 2017

Giải:

\(\dfrac{1}{2}.\left(\dfrac{1}{3}x-\dfrac{1}{5}\right)^2-\dfrac{1}{5}=-\dfrac{3}{40}\)

\(\Leftrightarrow\dfrac{1}{2}.\left(\dfrac{1}{3}x-\dfrac{1}{5}\right)^2=-\dfrac{3}{40}+\dfrac{1}{5}\)

\(\Leftrightarrow\dfrac{1}{2}.\left(\dfrac{1}{3}x-\dfrac{1}{5}\right)^2=\dfrac{1}{8}\)

\(\Leftrightarrow\left(\dfrac{1}{3}x-\dfrac{1}{5}\right)^2=\dfrac{1}{8}:\dfrac{1}{2}\)

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

\(\Leftrightarrow\left[{}\begin{matrix}\dfrac{1}{3}x-\dfrac{1}{5}=\dfrac{1}{2}\\\dfrac{1}{3}x-\dfrac{1}{5}=-\dfrac{1}{2}\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}\dfrac{1}{3}x=\dfrac{7}{10}\\\dfrac{1}{3}x=-\dfrac{3}{10}\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{21}{10}\\x=-\dfrac{9}{10}\end{matrix}\right.\)

Vậy ...

Chúc bạn học tốt!

18 tháng 10 2017

\(\dfrac{1}{2}.\left(\dfrac{1}{3}x-\dfrac{1}{5}\right)^2-\dfrac{1}{5}=-\dfrac{3}{40}\\ \dfrac{1}{2}\left(\dfrac{1}{3}x-\dfrac{1}{5}\right)^2=-\dfrac{3}{40}+\dfrac{1}{5}\\ \dfrac{1}{2}\left(\dfrac{1}{3}x-\dfrac{1}{5}\right)^2=\dfrac{1}{8}\\ \left(\dfrac{1}{3}x-\dfrac{1}{5}\right)^2=\dfrac{1}{8}:\dfrac{1}{2}\\\left(\dfrac{1}{3}x-\dfrac{1}{5}\right)^2=\dfrac{1}{4}\\ \left(\dfrac{1}{3}x-\dfrac{1}{5}\right)=\left(\pm\dfrac{1}{2}\right)^2\\ \Rightarrow\left\{{}\begin{matrix}\dfrac{1}{3}x-\dfrac{1}{5}=\dfrac{1}{2}\\\dfrac{1}{3}x-\dfrac{1}{5}=-\dfrac{1}{2}\end{matrix}\right.\Rightarrow\left\{{}\begin{matrix}\dfrac{1}{3}x=\dfrac{7}{10}\\\dfrac{1}{3}x=\dfrac{3}{10}\end{matrix}\right.\Rightarrow\left\{{}\begin{matrix}x=\dfrac{21}{10}\\x=\dfrac{9}{10}\end{matrix}\right. \)

Vậy \(x=\dfrac{21}{10}\) hoặc \(x=\dfrac{9}{10}\)

18 tháng 4 2017

a)

b) 4,5 : 0,3 = 2,25 : ( 0,1.x) => 0,1.x =

c)

d)


16 tháng 7 2017

Bạn hãy chỉ giúp mình cách viết phân số và hỗn số trên máy tính. Mình cảm ơn bạn nhiều lắm!hihivuihihi^ - ^

21 tháng 11 2022

1: =>1/3:x=3/5-2/3=9/15-10/15=-1/15

=>x=-1/3:1/15=5

2: \(\Leftrightarrow x\cdot\dfrac{2}{3}-3=\dfrac{2}{5}\cdot\left(-10\right)=-4\)

=>x*2/3=-1

=>x=-3/2

3: \(\Leftrightarrow\dfrac{8}{3}:x=\dfrac{25}{12}:\dfrac{-3}{50}=\dfrac{25}{12}\cdot\dfrac{-50}{3}\)

hay x=-48/625

9: =>x=-2*3/1,5=-4

8: =>2/3:x=5/2:-3/10=5/2*(-10)/3=-50/6=-25/3

=>x=-2/3:25/3=-2/3*3/25=-2/25

1/2+1/3<x<=1+1/2+1/5

=>5/6<x<=1+7/10

=>5/6<x<17/10

mà x là số nguyên

nên x=1

20 tháng 8 2017

Bn tách ra đi,mỏi tay lắm luôn ik,đánh máy mà.

20 tháng 8 2017

Lm từng câu thôi

14 tháng 10 2018

Bai 1: \(\left(-2\right)^3.\left(\dfrac{3}{4}-0,25\right):\left(2\dfrac{1}{4}-1\dfrac{1}{6}\right)\)

\(=\left(-8\right).\left(\dfrac{3}{4}-\dfrac{1}{4}\right):\left(\dfrac{9}{4}-\dfrac{7}{6}\right)\)

\(=\left(-8\right).\dfrac{1}{2}:\left(\dfrac{27}{12}-\dfrac{14}{12}\right)\)

\(=\left(-4\right):\dfrac{13}{12}\)

\(=\left(-4\right).\dfrac{12}{13}\)

\(=\dfrac{-48}{13}\)

Bai 2:

\(a,4\dfrac{1}{3}:\dfrac{x}{4}=6:0,3\)

\(\dfrac{13}{3}:\dfrac{x}{4}=20\)

\(\dfrac{x}{4}=\dfrac{13}{3}:20\)

\(\dfrac{x}{4}=\dfrac{13}{60}\)

\(x.60=4.13\)\(x.60=52\)\(x=\dfrac{13}{15}\)

Vay \(x=\dfrac{13}{15}\)

\(b,\left(2^3:4\right).2^{\left(x+1\right)}=64\)

\(\left(8:4\right).2^{x+1}=64\)

\(2.2^{x+1}=64\)

\(2^{x+1}=32\)

\(2^{x+1}=2^5\)\(x+1=5\)\(x=4\)

Vay \(x=4\)

Bài 2:

a: =>x^2=60

=>\(x=\pm2\sqrt{15}\)

b: =>2^2x+3=2^3x

=>3x=2x+3

=>x=3

c: \(\Leftrightarrow\sqrt{\dfrac{1}{2}x-2}\cdot\dfrac{1}{2}=1\)

\(\Leftrightarrow\sqrt{\dfrac{1}{2}x-2}=2\)

=>1/2x-2=4

=>1/2x=6

=>x=12