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\(\left(0,25-30\%.x\right).\frac{1}{3}-\frac{1}{4}=-5\frac{1}{6}\)
\(< =>\left(\frac{1}{4}-\frac{3x}{10}\right).\frac{1}{3}-\frac{1}{4}=-\frac{30}{6}\)
\(< =>\left(\frac{1}{4}-\frac{3x}{10}\right).\frac{1}{3}=-5+\frac{1}{4}=-\frac{19}{4}\)
\(< =>\frac{1}{4}-\frac{3x}{10}=\frac{-19}{4}.\frac{3}{1}=-\frac{57}{4}\)
\(< =>\frac{-3x}{10}=\frac{-57}{4}-\frac{1}{4}=-\frac{58}{4}\)
\(< =>-12x=-580\)
\(< =>12x=580< =>x=\frac{580}{12}=\frac{145}{3}\)
\(\left(0,25-30\%x\right).\frac{1}{3}-\frac{1}{4}=-5\frac{1}{6}\)
\(\left(\frac{1}{4}-\frac{3}{10}x\right)\frac{1}{3}-\frac{1}{4}=\frac{-31}{6}\)
\(\frac{1}{4}-\frac{3}{10}x=\left(\frac{-31}{6}+\frac{1}{4}\right)\div\frac{1}{3}\)
\(\frac{1}{4}-\frac{3}{10}x=\frac{-59}{4}\)
\(\frac{3}{10}x=\frac{1}{4}-\frac{-59}{4}\)
\(\frac{3}{10}x=15\Leftrightarrow x=50\)
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\(-3\frac{3}{5}-30\%x=0,45-1\frac{3}{4}x\)
\(-\frac{18}{5}-\frac{3}{10}x=\frac{9}{20}-\frac{7}{4}x\)
\(-\frac{3}{10}x+\frac{7}{4}x=\frac{18}{5}+\frac{9}{20}=\frac{72}{20}+\frac{9}{20}\)
\(\left(-\frac{3}{10}+\frac{7}{4}\right)x=\frac{81}{20}\)
\(\left(-\frac{6}{20}+\frac{35}{20}\right)x=\frac{81}{20}\)
\(\frac{29}{20}x=\frac{81}{20}\)
\(x=\frac{81}{20}:\frac{29}{20}=\frac{81}{20}\cdot\frac{20}{29}=\frac{81}{29}\)
Vậy \(x=\frac{81}{29}\)
Chúc bạn học tốt!^_^
sửa lại nè
\(\frac{41}{20}x=-\frac{72}{20}-\frac{9}{20}\)
\(\frac{41}{20}x=-\frac{81}{20}\)
\(x=\frac{-81}{20}:\frac{41}{20}\)
\(x=-\frac{81}{41}\)
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a)\(x-\frac{1}{4}=\frac{5}{8}\)
\(x=\frac{5}{8}+\frac{1}{4}\)
\(x=\frac{7}{8}\)
b)\(\frac{x}{12}=\frac{-1}{24}-\frac{1}{8}\)
\(\frac{x}{12}=\frac{-1}{24}+\frac{-1}{8}\)
\(\frac{x}{12}=\frac{-1}{6}\)
\(x=\frac{-1}{6}\times12\)
\(x=-2\)
a)x-1/4=5/8
=>x=5/8+1/4
x=7/8
b) x/12=-1/24-1/8
=>x/12=-1/6
=>x=-2
c).......... Tự làm
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\(x+x:0,25+x:0,5+x:0,125=0,45\)
\(\Rightarrow x+x:\dfrac{1}{4}+x:\dfrac{1}{2}+x:\dfrac{1}{8}=0,45\)
\(\Rightarrow x+4x+2x+8x=0,45\)
\(\Rightarrow15x=0,45\)
\(\Rightarrow x=0,3\)
Vậy x = 0,3
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a, (10/3:x).(-5/4)=-10/3
10/3:x=-10/3:(-5/4)
10/3:x=8/3
x=10/3:8/3
x=5/4
b,(-6/5+x):(-18/5)=-1/4
-6/5+x=-1/4.(-18/5)
-6/5+x=9/10
x=9/10-(-6/5)=9/10+6/5
x=21/10
c,-22/15.x+1/3=-2/5
-22/15.x=-2/5-1/3=-11/15
x=-11/15:(-22/15)
x=11/21
d,(0,25-30%x).1/3=-31/6+1/4=-59/12
1/4-3/10x=-59/12:1/3=-59/4
3/10x=1/4-(-59/4)=1/4+59/4=15
x=15:3/10
x=50
e,(0,5x-3/7):1/2=8/7
1/2x=8/7.1/2=4/7
x=4/7:1/2
x=8/7
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a) Ta có: \(\left(x-2\right)^3+\frac{8}{27}=0\)
\(\Leftrightarrow\left(x-2\right)^3=\frac{-8}{27}\)
\(\Leftrightarrow\left(x-2\right)^3=\left(-\frac{2}{3}\right)^3\)
\(\Leftrightarrow x-2=\frac{-2}{3}\)
hay \(x=\frac{-2}{3}+2=\frac{4}{3}\)
Vậy: \(x=\frac{4}{3}\)
b) Ta có: \(4\frac{1}{3}:\frac{x}{4}=6:0,3\)
\(\Leftrightarrow\frac{13}{3}\cdot\frac{4}{x}=20\)
\(\Leftrightarrow\frac{4}{x}=20:\frac{13}{3}=20\cdot\frac{3}{13}=\frac{60}{13}\)
hay \(x=\frac{13\cdot4}{60}=\frac{13}{15}\)
Vậy: \(x=\frac{13}{15}\)
c) Ta có: \(\left(0,25-30\%x\right)\cdot\frac{1}{3}-\frac{1}{4}=5\frac{1}{6}\)
\(\Leftrightarrow\left(\frac{1}{4}-\frac{3x}{10}\right)\cdot\frac{1}{3}=\frac{31}{6}+\frac{1}{4}=\frac{65}{12}\)
\(\Leftrightarrow\frac{1}{4}-\frac{3x}{10}=\frac{65}{12}:\frac{1}{3}=\frac{65}{12}\cdot3=\frac{65}{4}\)
\(\Leftrightarrow\frac{3x}{10}=\frac{1}{4}-\frac{65}{4}=-16\)
\(\Leftrightarrow3x=-160\)
hay \(x=\frac{-160}{3}\)
Vậy: \(x=\frac{-160}{3}\)
d) Ta có: \(\frac{x-2}{-\frac{2}{9}}=\frac{-2}{x-2}\)
\(\Leftrightarrow\left(x-2\right)^2=-2\cdot\left(-\frac{2}{9}\right)=\frac{4}{9}\)
\(\Leftrightarrow\left[{}\begin{matrix}x-2=\frac{2}{3}\\x-2=-\frac{2}{3}\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\frac{2}{3}+2\\x=\frac{-2}{3}+2\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\frac{8}{3}\\x=\frac{4}{3}\end{matrix}\right.\)
Vậy: \(x\in\left\{\frac{8}{3};\frac{4}{3}\right\}\)
a/ (x - 2)3 + \(\frac{8}{27}\) = 0
=> (x - 2)3 = 0 - \(\frac{8}{27}\) = \(\frac{-8}{27}\)
=> x - 2 = \(-\frac{2}{3}\)
=> x = \(-\frac{2}{3}+2=\frac{4}{3}\)
b/ \(4\frac{1}{3}:\frac{x}{4}=6:0,3\)
=> \(4\frac{1}{3}:\frac{x}{4}=6:\frac{3}{10}=6.\frac{10}{3}=20\)
=> \(\frac{x}{4}=4\frac{1}{3}:20=\frac{13}{3}.\frac{1}{20}=\frac{13}{60}\)
=> \(x=\frac{13}{60}.4=\frac{13}{15}\)
c/ \(\left(0,25-30\%x\right).\frac{1}{3}-\frac{1}{4}=5\frac{1}{6}\)
=> \(\left(0,25-30\%x\right).\frac{1}{3}=5\frac{1}{6}+\frac{1}{4}=\frac{65}{12}\)
=> \(0,25-\frac{30}{100}x=\frac{65}{12}:\frac{1}{3}=\frac{65}{12}.3=\frac{65}{4}\)
=> \(\frac{3}{10}x=0,25-\frac{65}{4}=\frac{1}{4}-\frac{65}{4}=-\frac{64}{4}=-16\)
=> \(x=-16:\frac{3}{10}=-16.\frac{10}{3}=-\frac{160}{3}\)
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a, 0,25 - x = -0,75
x = 0,25 - -0,75
x = 1
b,x:(-3)= -\(\frac{2}{3}\)
x = -\(\frac{2}{3}\) >< -3
x = -2
c,(1,1.x-9).\(\frac{2}{5}\)=80%
1,1 >< x -9 = \(\frac{80}{100}\) : \(\frac{2}{5}\)
1,1 >< x -9 = 2
1,1 >< x = 2 + 9
1,1 >< x = 11
x =11 : 1,1
x = 10
d,2.x-30%.x=-1,7
x >< (2-0,3)=1,7
x >< 0,7 = 1,7
x = 1,7 : 0,7
x = 2.42857142857