`x-2,9=-5,8+1,4`
`x-2,9=-4,4`
`x=-4,4+2,9`
`x=-1,5`
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`|x-2/5| = 1 1/5`
`|x-2/5| =6/5`
`@TH1:`
`x-2/5=6/5`
`x=6/5+2/5`
`x=8/5`
`@TH2:`
`x-2/5=-6/5`
`x=-6/5+2/5`
`x=-4/5`
Vậy `x={-4/5; 8/5}`
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`(x-3/7)^2 = 4/49`
\(\left(x-\dfrac{3}{7}\right)^2=\left(\pm\dfrac{2}{7}\right)^2\)
`@TH1:`
`x-3/7=2/7`
`x=2/7+3/7`
`x=5/7`
`@TH2:`
`x-3/7=-2/7`
`x=-2/7+3/7`
`x=1/7`
Vậy `x={1/7; 5/7}`
\(a,x-2,9=-5,8+1,4\)
\(x-2,9=-4,4\)
\(x=-4,4+2,9\)
\(x=-1,5\)
\(b,\left|x-\dfrac{2}{5}\right|=1\dfrac{1}{5}\)
\(\left|x-\dfrac{2}{5}\right|=\dfrac{6}{5}\)
\(\Rightarrow\left\{{}\begin{matrix}x-\dfrac{2}{5}=\dfrac{6}{5}\\x-\dfrac{2}{5}=-\dfrac{6}{5}\end{matrix}\right.\)
\(\Rightarrow\left\{{}\begin{matrix}x=\dfrac{6}{5}+\dfrac{2}{5}\\x=-\dfrac{6}{5}+\dfrac{2}{5}\end{matrix}\right.\)
\(\Rightarrow\left\{{}\begin{matrix}x=\dfrac{8}{5}\\x=\dfrac{-4}{5}\end{matrix}\right.\)
\(c,\left(x-\dfrac{3}{7}\right)^2=\dfrac{4}{49}\)
\(x-\dfrac{3}{7}=\pm\dfrac{2}{7}\)
\(\Rightarrow\left\{{}\begin{matrix}x-\dfrac{3}{7}=-\dfrac{2}{7}\\x-\dfrac{3}{7}=\dfrac{2}{7}\end{matrix}\right.\)
\(\Rightarrow\left\{{}\begin{matrix}x=-\dfrac{2}{7}+\dfrac{3}{7}\\x=\dfrac{2}{7}+\dfrac{3}{7}\end{matrix}\right.\)
\(\Rightarrow\left\{{}\begin{matrix}x=\dfrac{1}{7}\\x=\dfrac{5}{7}\end{matrix}\right.\)
