\(|\)2,5 - x\(|\) = 1,3
1,6 - \(|\)x - 0,2\(|\) = 0
13x = 169
\(\dfrac{-2\dfrac{ }{ }}{x}\) = \(\dfrac{-x}{\dfrac{8}{25}}\)
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\(a,=\dfrac{x^3-\left(x-1\right)\left(x^2+x+1\right)}{1-x}=\dfrac{x^3-x^3+1}{1-x}=\dfrac{1}{1-x}\\ b,=\dfrac{2x+x^2+3x+2+2-x}{\left(x+2\right)^2}=\dfrac{\left(x+2\right)^2}{\left(x+2\right)^2}=1\)
\(=\dfrac{2x^2-x-x-1+2-x^2}{x-1}=\dfrac{x^2-2x+1}{x-1}=\dfrac{\left(x-1\right)^2}{x-1}=x-1\)
\(\left(x:2,2\right)\times\dfrac{1}{6}=\dfrac{-3}{8}\times\left(0,5-1\dfrac{3}{5}\right)\)
\(\Rightarrow\left(x:2,2\right)\times\dfrac{1}{6}=\dfrac{-3}{8}\times\left(\dfrac{1}{2}-\dfrac{8}{5}\right)\)
\(\Rightarrow\left(x:2,2\right)\times\dfrac{1}{6}=\dfrac{-3}{8}\times\dfrac{11}{10}\)
\(\Rightarrow\left(x:2,2\right)\times\dfrac{1}{6}=\dfrac{33}{80}\)
\(\Rightarrow x:2,2=\dfrac{33}{80}:\dfrac{1}{6}\)
\(\Rightarrow x:2,2=\dfrac{99}{40}\)
\(\Rightarrow x=\dfrac{99}{40}\times2,2\)
\(\Rightarrow x=\dfrac{1089}{200}\)
=>(x:2,2)*1/6=-3/8(1/2-8/5)=33/80
=>x:2,2=99/40
=>x=1089/200
a) \(x=\dfrac{-2}{7}+\dfrac{9}{7}=1\)
b) \(\dfrac{x}{3}=\dfrac{2}{5}+\dfrac{-4}{3}\)
\(\dfrac{x}{3}=\dfrac{-14}{15}\)
\(\Rightarrow x=\dfrac{3.-14}{15}=\dfrac{-14}{5}\)
\(x=\dfrac{-2}{7}+\dfrac{9}{7}\)
\(x=1\)
a) Ta có: \(\left|2.5-x\right|=1.3\)
\(\Leftrightarrow\left|x-2.5\right|=1.3\)
\(\Leftrightarrow\left[{}\begin{matrix}x-2.5=1.3\\x-2.5=-1.3\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=3.8\\x=-1.3+2.5=1.2\end{matrix}\right.\)
Vậy: \(x\in\left\{3.8;1.2\right\}\)
b) Ta có: \(1.6-\left|x-0.2\right|=0\)
\(\Leftrightarrow\left|x-0.2\right|=1.6\)
\(\Leftrightarrow\left[{}\begin{matrix}x-0.2=1.6\\x-0.2=-1.6\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=1.8\\x=-1.4\end{matrix}\right.\)
Vậy: \(x\in\left\{1.8;-1.4\right\}\)
c) Ta có: \(13^x=169\)
\(\Leftrightarrow13^x=13^2\)
\(\Leftrightarrow x=2\)
Vậy: x=2
d) Ta có: \(\dfrac{-2}{x}=\dfrac{-x}{\dfrac{8}{25}}\)
\(\Leftrightarrow\dfrac{2}{x}=\dfrac{x}{\dfrac{8}{25}}\)
\(\Leftrightarrow x^2=\dfrac{16}{25}\)
hay \(x\in\left\{\dfrac{4}{5};-\dfrac{4}{5}\right\}\)
Vậy: \(x\in\left\{\dfrac{4}{5};-\dfrac{4}{5}\right\}\)
\(|2,5-x|=1,3\)
\(\Rightarrow2,5-x=1,3\) hoặc -(2,5-x)=1,3
=>x=2,5-1,3 x-2,5=1,3
=>x=1,2 x=1,3+2,5=3,8
Vậy \(x\in\left\{1,2;3,8\right\}\)
\(1,6-|x-0,2|=0\Rightarrow|x-0,2|=1,6\)
=> x-0,2=1,6 hoặc -(x-0,2)=1,6
=>x=1,6+0,2 0,2-x=1,6
=>x=3,8 x=0,2-1,6=-1,4
Vậy \(x\in\left\{3,8;-1,4\right\}\)
\(13^x=169\Rightarrow13^x=13^2\Rightarrow x=2\)
\(\dfrac{-2}{x}=\dfrac{-x}{\dfrac{8}{25}}\Rightarrow-2\times\dfrac{8}{25}=-x\times x\Rightarrow\dfrac{-16}{25}=-x^2\Rightarrow\dfrac{16}{25}=x^2\Rightarrow x^2=\left(\dfrac{4}{5}\right)^2=\left(-\dfrac{4}{5}\right)^2\)
\(\Rightarrow x=\dfrac{4}{5}\) hoặc \(x=-\dfrac{4}{5}\)