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23 tháng 8 2022
1: \(\Leftrightarrow\left(x+1\right)^2=4\)
=>x+1=2 hoặc x+1=-2
=>x=1 hoặc x=-3
2: \(\Leftrightarrow7x-21=5x+25\)
=>2x=46
=>x=23
3: \(\Leftrightarrow x^2+4x+3=x^2+0.5x+4x+2\)
=>4,5x+2=4x+3
=>x=1
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
10 tháng 9 2017
a/ \(\dfrac{1}{3}-\dfrac{2}{5}+3x=\dfrac{3}{4}\)
\(\Leftrightarrow\dfrac{-1}{15}+3x=\dfrac{3}{4}\)
\(\Leftrightarrow3x=\dfrac{49}{60}\)
\(\Leftrightarrow x=\dfrac{49}{180}\)
Vậy....
b/ \(\dfrac{3}{2}-1+4x=\dfrac{2}{3}-7x\)
\(\Leftrightarrow\dfrac{1}{2}+4x=\dfrac{2}{3}-7x\)
\(\Leftrightarrow4x+7x=\dfrac{2}{3}-\dfrac{1}{2}\)
\(\Leftrightarrow11x=\dfrac{1}{6}\)
\(\Leftrightarrow x=\dfrac{1}{66}\)
Vậy....
c/ \(2\left(\dfrac{3}{4}-5x\right)=\dfrac{4}{5}-3x\)
\(\Leftrightarrow\dfrac{3}{2}-10x=\dfrac{4}{5}-3x\)
\(\Leftrightarrow-10x+3x=\dfrac{4}{5}-\dfrac{3}{2}\)
\(\Leftrightarrow-7x=-\dfrac{7}{10}\)
\(\Leftrightarrow x=-\dfrac{1}{10}\)
Vậy .....
10 tháng 9 2017
d/ \(4\left(\dfrac{1}{2}-x\right)-5\left(x-\dfrac{3}{10}\right)=\dfrac{7}{4}\)
\(\Leftrightarrow2-4x-5x-\dfrac{3}{2}=\dfrac{7}{4}\)
\(\Leftrightarrow2+\left(-4x\right)+\left(-5x\right)+\left(\dfrac{-3}{2}\right)=\dfrac{7}{4}\)
\(\Leftrightarrow-9x+\dfrac{1}{2}=\dfrac{7}{4}\)
\(\Leftrightarrow-9x=\dfrac{5}{4}\)
\(\Leftrightarrow x=-\dfrac{5}{36}\)
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
FC
15 tháng 10 2018
a, \(\dfrac{3x-5}{\dfrac{2}{\dfrac{3}{4}}}=\dfrac{4}{5}\)
<=>(3x - 5) : \(\dfrac{2}{3}\): 4 = \(\dfrac{4}{5}\)
(3x - 5) : \(\dfrac{2}{3}\) . \(\dfrac{1}{4}\)= \(\dfrac{4}{5}\)
(3x - 5) : \(\dfrac{2}{12}\) = \(\dfrac{4}{5}\)
(3x - 5) : \(\dfrac{1}{6}\) = \(\dfrac{4}{5}\)
(3x - 5) = \(\dfrac{4}{5}\) . \(\dfrac{1}{6}\)
(3x - 5) = \(\dfrac{2.1}{5.3}=\dfrac{2}{15}\)
3x = \(\dfrac{2+75}{15}\)= \(\dfrac{77}{15}\)
x = \(\dfrac{77}{15}\). \(\dfrac{1}{3}\) = \(\dfrac{77}{45}\)
28 tháng 6 2017
a, \(\dfrac{5}{6}-\left|2-x\right|=\dfrac{1}{3}\Rightarrow\dfrac{5}{6}-\dfrac{1}{3}=\left|2-x\right|\)
<=> \(\dfrac{1}{2}=\left|2-x\right|\) \(\Leftrightarrow\left[{}\begin{matrix}2-x=\dfrac{1}{2}\\2-x=\dfrac{-1}{2}\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{3}{2}\\x=\dfrac{5}{2}\end{matrix}\right.\)
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Mấy câu sau tương tự thôi
21 tháng 1 2018
a)\(\dfrac{3}{2}hay\dfrac{-3}{2}\)
b)\(\dfrac{13}{20}hay\dfrac{-13}{20}\)
c)\(\dfrac{11}{6}hay\dfrac{-11}{6}\)
d)\(\dfrac{4}{3}hay\dfrac{-4}{3}\)
e)\(\dfrac{1}{5}hay\dfrac{-1}{5}\)
Đây là câu trả lời của mình
Hay có nghĩa là hoặc
2 tháng 10 2017
câu E
\(\left\{{}\begin{matrix}x\ne\dfrac{5}{2}\\\left(2x-5\right)\left(5-2x\right)=-\left(\dfrac{3}{2}\right)^4\end{matrix}\right.\) \(\Leftrightarrow\left\{{}\begin{matrix}x\ne\dfrac{5}{2}\\\left|2x-5\right|=\left(\dfrac{3}{2}\right)^2\end{matrix}\right.\)
\(\left[{}\begin{matrix}\left\{{}\begin{matrix}x< \dfrac{5}{2}\\2x-5=-\left(\dfrac{3}{2}\right)^2\Rightarrow x=\dfrac{11}{8}< \dfrac{5}{2}\left(n\right)\end{matrix}\right.\\\left\{{}\begin{matrix}x>\dfrac{5}{2}\\2x-5=\left(\dfrac{3}{2}\right)^2\Rightarrow x=\dfrac{29}{8}>\dfrac{5}{2}\left(n\right)\end{matrix}\right.\end{matrix}\right.\)
câu F (bạn cho vào lớp 7.2=lớp 14 nhé. )
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
HL
11 tháng 7 2017
\(\dfrac{x+1}{1}+\dfrac{2x+3}{3}+\dfrac{3x+5}{5}+...+\dfrac{10x+19}{19}=12+\dfrac{4}{3}+\dfrac{6}{5}+...+\dfrac{20}{19}\)
\(x+1+\dfrac{2x}{3}+1+\dfrac{3x}{5}+1+...+\dfrac{10x}{19}+1-12-\dfrac{4}{3}-\dfrac{6}{5}-...-\dfrac{20}{19}=0\)
\(x+\dfrac{2x}{3}-\dfrac{4}{3}+\dfrac{3x}{5}-\dfrac{6}{5}+...+\dfrac{10x}{19}-\dfrac{20}{19}+10-12=0\)
\(x-2+\dfrac{2x-4}{3}+\dfrac{3x-6}{5}+...+\dfrac{10x-20}{19}=0\)
\(x-2+\dfrac{2\left(x-2\right)}{3}+\dfrac{3\left(x-2\right)}{5}+...+\dfrac{10\left(x-2\right)}{19}=0\)
\(\left(x-2\right)\left(\dfrac{2}{3}+\dfrac{3}{5}+...+\dfrac{10}{19}\right)=0\)
Ta thấy \(\left(\dfrac{2}{3}+\dfrac{3}{5}+...+\dfrac{10}{19}\right)>0\)
\(\Rightarrow x-2=0\Rightarrow x=2\)
`#3107.101107`
\(\dfrac{3x}{5}=\dfrac{x-1}{3}\)
\(\Rightarrow3x\cdot3=5\left(x-1\right)\)
\(\Rightarrow5\left(x-1\right)=9x\)
\(\Rightarrow5x-5=9x\)
\(\Rightarrow5x-9x=5\)
\(\Rightarrow-4x=5\)
\(\Rightarrow x=-\dfrac{5}{4}\)
Vậy, \(x=-\dfrac{5}{4}.\)