tìm x biết (2x-1)^3=8
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\(\frac{1-2x}{10}+\frac{3-2x}{8}+\frac{23-2x}{6}=0\)
\(\Leftrightarrow\frac{1}{10}-\frac{2x}{10}+\frac{3}{8}-\frac{2x}{8}+\frac{23}{6}-\frac{2x}{6}=0\)
\(\Leftrightarrow\frac{1}{10}-\frac{x}{5}+\frac{3}{8}-\frac{x}{4}+\frac{23}{6}-\frac{x}{3}=0\)
\(\Leftrightarrow\left(\frac{1}{10}+\frac{3}{8}+\frac{23}{6}\right)-\left(\frac{x}{3}+\frac{x}{4}+\frac{x}{5}\right)=0\)
\(\Leftrightarrow\frac{517}{120}-\left(\frac{x}{3}+\frac{x}{4}+\frac{x}{5}\right)=0\)
\(\Leftrightarrow x\left(\frac{1}{3}+\frac{1}{4}+\frac{1}{5}\right)=\frac{517}{120}\)
\(\Leftrightarrow x.\frac{47}{60}=\frac{517}{120}\)
\(\Rightarrow x=\frac{517}{120}:\frac{47}{60}=\frac{11}{2}\)
Vậy \(x=\frac{11}{2}\)
(1-2x)/10+(3-2x)/8+(23-2x)/6=0
[48(1-2x)+60(3-2x)+80(23-2x)]/480=0
48-96x+180-120x+1840-160x=0
2068-376x=0
-376x=-2068
x=11/2
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a) \(\left(x-1\right)\left(2x+3\right)-x\left(x-1\right)=0\)
\(\Leftrightarrow\left(x-1\right)\left(2x+3-x\right)=0\)
\(\Leftrightarrow\left(x-1\right)\left(x+3\right)=0\)
\(\Rightarrow\orbr{\begin{cases}x-1=0\\x+3=0\end{cases}\Rightarrow\orbr{\begin{cases}x=1\\x=-3\end{cases}}}\)
Vậy \(x=1;-3\)
b) \(x^2-4x+8=2x-1\)
\(\Leftrightarrow x^2-4x+8-2x+1=0\)
\(\Leftrightarrow x^2-6x+9=0\)
\(\Leftrightarrow\left(x-3\right)^2=0\)
\(\Leftrightarrow x-3=0\)
\(\Leftrightarrow x=3\)
Vậy x=3
a) \(\left(x-1\right)\left(2x+3\right)-x\left(x-1\right)=0\)
\(\Leftrightarrow\left(x-1\right)\left(2x+3-x\right)=0\)
\(\Leftrightarrow\left(x-1\right)\left(x+3\right)=0\)
\(\Rightarrow\orbr{\begin{cases}x-1=0\\x+3=0\end{cases}\Rightarrow\orbr{\begin{cases}x=1\\x=-3\end{cases}}}\)
Vậy \(x=1;-3\)
b) \(x^2-4x+8=2x-1\)
\(\Leftrightarrow x^2-4x+8-2x+1=0\)
\(\Leftrightarrow x^2-6x+9=0\)
\(\Leftrightarrow\left(x-3\right)^2=0\)
\(\Leftrightarrow x-3=0\)
\(\Leftrightarrow x=3\)
Vậy \(x=3\)
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(2x-1)^3=8 suy ra 2x-1 = 2
2x=3
x=3/2
\(\Leftrightarrow\left(2x-1\right)^3=2^3\)
\(\Rightarrow2x-1=2\)
\(\Leftrightarrow2x=1\)
\(\Leftrightarrow x=\frac{1}{2}\)