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a) \(\frac{3}{4}.x+40\%=\frac{-1}{4}\)
\(\frac{3}{4}.x+\frac{2}{5}=\frac{-1}{4}\)
\(\frac{3}{4}.x=\frac{-13}{20}\)
\(x=\frac{-13}{15}\)
Vậy \(x=\frac{-13}{15}\)
c) \(|x-1|=2^3+\left(-5\right)\)
\(|x-1|=3\)
\(\Leftrightarrow\orbr{\begin{cases}x-1=3\\x-1=-3\end{cases}\Leftrightarrow\orbr{\begin{cases}x=4\\x=-2\end{cases}}}\)
Vậy \(x\in\left\{-2;4\right\}\)
c)\(\frac{1}{2}x+\frac{1}{8}x=\frac{3}{4}\)
\(\Rightarrow x.\left(\frac{1}{2}-\frac{1}{8}\right)=\frac{3}{4}\)
\(\Rightarrow x.\frac{3}{8}=\frac{3}{4}\)
=>x\(=\frac{3}{4}:\frac{3}{8}\)
=>x=\(2\)
a)\(x+\frac{1}{6}=\frac{-3}{8}\)
=>\(x=\frac{-3}{8}-\frac{1}{6}\)
=>\(x=\frac{-9}{24}-\frac{4}{24}\)
=>\(x=\frac{-13}{24}\)
b)\(2-\left|\frac{3}{4}-x\right|=\frac{7}{12}\)
=>\(\left|\frac{3}{4}-x\right|=2-\frac{7}{12}\)
=>\(\left|\frac{3}{4}-x\right|=\frac{24}{12}-\frac{7}{12}\)
\(\Rightarrow\left|\frac{3}{4}-x\right|=\frac{17}{12}\)
TH1: \(\frac{3}{4}-x=\frac{17}{12}\)
=>x=\(\frac{3}{4}-\frac{17}{12}\)
=>x=\(x=-\frac{2}{3}\)
TH2:\(\frac{3}{4}-x=-\frac{17}{12}\)
=>\(x=\frac{3}{4}-\left(-\frac{17}{12}\right)\)
=>x=\(x=\frac{13}{6}\)
Dzồi nhìu phết
\(\left(x-\frac{1}{3}\right)^2-\frac{1}{4}=0\)
=>\(\left(x-\frac{1}{3}\right)^2=\frac{1}{4}=\left(\frac{1}{2}\right)^2=\left(-\frac{1}{2}\right)^2\)
=>\(x-\frac{1}{3}=\frac{1}{2}\)hoặc \(x-\frac{1}{3}=-\frac{1}{2}\)
=>x=1/2+1/3hoawcj x=-1/2+1/3
=>x=5/6 hoặc x=-1/6
Bài 2:
\(M=\frac{1}{2.3}+\frac{1}{3.4}+\frac{1}{4.5}+...+\frac{1}{2008.2009}\)
\(\Rightarrow M=\frac{3-2}{2.3}+\frac{4-3}{3.4}+\frac{5-4}{4.5}+...+\frac{2009-2008}{2008.2009}\)
\(\Rightarrow M=\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+...+\frac{1}{2008}-\frac{1}{2009}=\frac{1}{2}-\frac{1}{2009}\)
Bài 1:
Ta có: \(\frac{x}{2}+\frac{x}{3}=x\left(\frac{1}{2}+\frac{1}{3}\right)=\frac{5}{6}x=\frac{1}{4}\Rightarrow x=\frac{3}{10}\)
Bài 1:
a) Ta có: \(\frac{7}{8}\cdot\frac{4}{9}+\frac{1}{14}:\frac{5}{14}\)
\(=\frac{28}{72}+\frac{1}{14}\cdot\frac{14}{5}\)
\(=\frac{28}{72}+\frac{1}{5}\)
\(=\frac{140}{360}+\frac{72}{360}\)
\(=\frac{212}{360}=\frac{53}{90}\)
Bài 2:
a) Ta có: \(\frac{2}{3}x+\frac{1}{4}x=\frac{-22}{27}\)
\(\Leftrightarrow x\cdot\left(\frac{2}{3}+\frac{1}{4}\right)=\frac{-22}{27}\)
\(\Leftrightarrow x\cdot\frac{11}{12}=\frac{-22}{27}\)
\(\Leftrightarrow x=\frac{-22}{27}:\frac{11}{12}=\frac{-22}{27}\cdot\frac{12}{11}=-\frac{8}{9}\)
Vậy: \(x=\frac{-8}{9}\)
a) \(\left(x+1\right)-\frac{x+1}{3}=\frac{5\left(x+1\right)-1}{6}\)
\(\Leftrightarrow6\left(x+1\right)-2\left(x+1\right)=5\left(x+1\right)-1\)
\(\Leftrightarrow6x+6-2x-2=5x+5-1\)
\(\Leftrightarrow6x-2x-5x=5-1-6+2\)
\(\Leftrightarrow-x=0\)
\(\Leftrightarrow x=0\)
b) \(\left(1-x\right)^2+\left(x+2\right)^2=2x\left(x-3\right)-7\)
\(\Leftrightarrow1-2x+x^2+x^2+4x+4=2x^2-6x-7\)
\(\Leftrightarrow2x^2+2x+5=2x^2-6x-7\)
\(\Leftrightarrow2x+6x=-7-5\)
\(\Leftrightarrow8x=-12\)
\(\Leftrightarrow x=-\frac{3}{2}\)
c) \(2+\frac{x-2}{2}-\frac{2x-4}{3}-\frac{5}{6}\left(2-x\right)=0\)
\(\Leftrightarrow2+\frac{x}{2}-1-\frac{2}{3}x+\frac{4}{3}-\frac{5}{3}+\frac{5}{6}x=0\)
\(\Leftrightarrow\frac{x}{2}-\frac{2}{3}x+\frac{5}{6}x=-2+1-\frac{4}{3}+\frac{5}{3}\)
\(\Leftrightarrow\frac{2}{3}x=-\frac{2}{3}\)
\(\Leftrightarrow x=-1\)
3-(3/4+x-1/3):2/3=1/2
3-(3/4+x-1/3)=1/2*2/3
3-(3/4+x-1/3)=2/6
3/4+x-1/3=3-2/6
3/4+x-1/3=8/3
3/4+x=8/3+1/3
3/4+x=3
x=3-3/4
x=9/4