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14 tháng 9 2017
a/ \(\dfrac{x}{-\dfrac{5}{9}}=\dfrac{\dfrac{4}{3}}{-\dfrac{2}{5}}\)
\(\Leftrightarrow x.\left(\dfrac{-2}{5}\right)=\left(\dfrac{-5}{9}\right).\dfrac{4}{3}\)
\(\Leftrightarrow x.\left(-\dfrac{2}{5}\right)=\dfrac{-20}{27}\)
\(\Leftrightarrow x=\)\(\dfrac{-54}{100}\)
b/ tương tự
14 tháng 9 2017
b/ \(\dfrac{7}{\dfrac{5}{3x}}=\dfrac{-\dfrac{4}{9}}{\dfrac{5}{6}}\)
\(\Leftrightarrow\dfrac{5}{3x}.\left(-\dfrac{4}{9}\right)=7.\dfrac{5}{6}\)
\(\Leftrightarrow\dfrac{5}{3x}.\left(-\dfrac{4}{9}\right)=\dfrac{35}{6}\)
\(\Leftrightarrow\dfrac{5}{3x}=\dfrac{-315}{24}\)
\(\Leftrightarrow3x\left(-315\right)=5.24\)
\(\Leftrightarrow3x\left(-315\right)=120\)
tự tính tiếp, đang lười
1 tháng 12 2022
a: \(\Leftrightarrow\dfrac{3}{4}:\dfrac{22}{9}-\left|3x-\dfrac{8}{3}\right|=\dfrac{3}{4}\)
\(\Leftrightarrow\left|3x-\dfrac{8}{3}\right|=\dfrac{3}{4}\cdot\dfrac{9}{22}-\dfrac{3}{4}=\dfrac{3}{4}\cdot\dfrac{-13}{22}=\dfrac{-39}{88}\)(loại)
b: \(\Leftrightarrow\left[{}\begin{matrix}3x-2=x-\dfrac{1}{3}\\3x-2=\dfrac{1}{3}-x\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}2x=\dfrac{5}{3}\\4x=\dfrac{7}{3}\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{5}{6}\\x=\dfrac{7}{12}\end{matrix}\right.\)
24 tháng 9 2022
1: \(\Leftrightarrow3x+4=2\)
=>3x=-2
=>x=-2/3
2: \(\Leftrightarrow7x-7=6x-30\)
=>x=-23
3: =>\(5x-5=3x+9\)
=>2x=14
=>x=7
4: =>9x+15=14x+7
=>-5x=-8
=>x=8/5
14 tháng 9 2017
a/ \(\dfrac{\dfrac{-5}{12}}{\left|\dfrac{2}{3}x+\dfrac{1}{2}\right|}=\dfrac{\dfrac{-4}{9}}{\dfrac{8}{15}}\)
\(\Leftrightarrow\left|\dfrac{2}{3}x+\dfrac{1}{2}\right|.\left(-\dfrac{4}{9}\right)=\left(-\dfrac{5}{12}\right).\left(\dfrac{8}{15}\right)\)
\(\Leftrightarrow\left|\dfrac{2}{3}x+\dfrac{1}{2}\right|.\left(-\dfrac{4}{9}\right)=\dfrac{-2}{9}\)
\(\Leftrightarrow\left|\dfrac{2}{3}x+\dfrac{1}{2}\right|=\dfrac{1}{2}\)
\(\Leftrightarrow\left[{}\begin{matrix}\dfrac{2}{3}x+\dfrac{1}{2}=\dfrac{1}{2}\\\dfrac{2}{3}x+\dfrac{1}{2}=-\dfrac{1}{2}\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}\dfrac{2}{3}x=0\\\dfrac{2}{3}x=-1\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=0\\x=-\dfrac{3}{2}\end{matrix}\right.\)
Vậy ....
27 tháng 11 2022
b: =>(3x-1)(3x+1)(2x+3)=0
hay \(x\in\left\{\dfrac{1}{3};-\dfrac{1}{3};-\dfrac{3}{2}\right\}\)
c: \(\Leftrightarrow\left|2x-\dfrac{1}{3}\right|=\dfrac{5}{6}+\dfrac{3}{4}=\dfrac{19}{12}\)
=>2x-1/3=19/12 hoặc 2x-1/3=-19/12
=>2x=23/12 hoặc 2x=-15/12=-5/4
=>x=23/24 hoặc x=-5/8
d: \(\Leftrightarrow-\dfrac{5}{6}\cdot x+\dfrac{3}{4}=-\dfrac{3}{4}\)
=>-5/6x=-3/2
=>x=3/2:5/6=3/2*6/5=18/10=9/5
e: =>2/5x-1/2=3/4 hoặc 2/5x-1/2=-3/4
=>2/5x=5/4 hoặc 2/5x=-1/4
=>x=5/4:2/5=25/8 hoặc x=-1/4:2/5=-1/4*5/2=-5/8
f: =>14x-21=9x+6
=>5x=27
=>x=27/5
h: =>(2/3)^2x+1=(2/3)^27
=>2x+1=27
=>x=13
i: =>5^3x*(2+5^2)=3375
=>5^3x=125
=>3x=3
=>x=1
QD
27 tháng 7 2017
h) \(5^x+5^{x+2}=650\)
\(\Leftrightarrow5^x+5^x.5^2=650\)
\(\Leftrightarrow5^x\left(1+25\right)=650\)
\(\Leftrightarrow5^x.26=650\)
\(\Leftrightarrow5^x=25\)
\(\Leftrightarrow x=2\)
haizzz,đăng ít thôi,chứ nhìn hoa mắt quá =.=
DG
1 tháng 8 2017
bây định làm j ở chỗ này vậy??? có j ib ns vs nhao chớ sao ns ở đây
26 tháng 5 2022
a: \(\Leftrightarrow-\dfrac{2}{3}\cdot\dfrac{4-6-9}{12}\ge x\ge-\dfrac{13}{3}\cdot\dfrac{3-1}{6}\)
\(\Leftrightarrow-\dfrac{2}{3}\cdot\dfrac{-11}{12}\ge x\ge\dfrac{-13}{3}\cdot\dfrac{1}{3}\)
\(\Leftrightarrow\dfrac{22}{36}\ge x\ge\dfrac{-13}{9}\)
mà x là số nguyên
nên \(x\in\left\{0;-1\right\}\)
b: \(\Leftrightarrow\dfrac{21}{100}+\dfrac{75}{100}-\dfrac{220}{100}>=2x-1>=-3-\dfrac{1}{2}+3+\dfrac{1}{5}\)
\(\Leftrightarrow\dfrac{-124}{100}\ge2x-1\ge\dfrac{-3}{10}\)
\(\Leftrightarrow-\dfrac{124}{100}+1\ge2x>=\dfrac{-3}{10}+1\)
\(\Leftrightarrow\dfrac{-3}{25}\ge2x\ge\dfrac{7}{10}\)(vô lý)
=>x không có giá trị
c: \(\Leftrightarrow43+\dfrac{1}{2}-39-\dfrac{1}{5}\le-3x+4\le9+\dfrac{1}{5}+50+\dfrac{1}{7}\)
\(\Leftrightarrow3+\dfrac{3}{10}\le-3x+4\le59+\dfrac{12}{35}\)
\(\Leftrightarrow\dfrac{33}{10}-4\le-3x\le59+\dfrac{12}{35}-4\)
\(\Leftrightarrow\dfrac{-7}{10}\le-3x\le\dfrac{1937}{35}\)
\(\Leftrightarrow\dfrac{7}{30}\ge x\ge-\dfrac{1937}{105}\)
mà x là số nguyên
nên \(x\in\left\{0;-1;-2;...;-18\right\}\)
19 tháng 6 2018
8)\(\frac{4}{9}:\left(-\frac{1}{7}\right)+6\frac{5}{9}:\left(-\frac{1}{7}\right)\)
=\(\frac{4}{9}:\left(-\frac{1}{7}\right)+\frac{59}{9}:\left(-\frac{1}{7}\right)\)
=\(\left(\frac{4}{9}+\frac{59}{9}\right).\left(-7\right)\)
=7.(-7)
=-49
22 tháng 5 2022
a: \(\dfrac{31-2x}{x+23}=\dfrac{9}{4}\)
=>121-8x=9x+207
=>-17x=86
hay x=-86/17
b: \(\dfrac{\left|2x-1\right|}{\dfrac{1}{2}}=\dfrac{18}{5}\)
=>|2x-1|=9/5
=>2x-1=9/5 hoặc 2x-1=-9/5
=>2x=14/5 hoặc 2x=-4/5
=>x=7/5 hoặc x=-2/5
( 3x - \(\dfrac{1}{2}\))2 = \(\dfrac{4}{9}\)
=> 3x - \(\dfrac{1}{2}\)= \(\dfrac{4}{9}\): 2
=> 3x - \(\dfrac{1}{2}\)= \(\dfrac{2}{9}\)
=> 3x = \(\dfrac{2}{9}\)+ \(\dfrac{1}{2}\)
=> 3x= \(\dfrac{13}{18}\)
=> x = \(\dfrac{13}{54}\)
Chúc bạn học tốt !
\(\left(3x-\dfrac{1}{2}\right).2=\dfrac{4}{9}\)
\(\Rightarrow\left(3x-\dfrac{1}{2}\right)=\dfrac{4}{9}:2\)
\(\Rightarrow\left(3x-\dfrac{1}{2}\right)=\dfrac{2}{9}\)
\(\Rightarrow3x=\dfrac{2}{9}+\dfrac{1}{2}\)
\(\Rightarrow3x=\dfrac{13}{18}\)
\(\Rightarrow x=\dfrac{13}{18}:3\)
\(\Rightarrow x=\dfrac{13}{54}\)
Chúc bạn học tốt!