$\text{Đáp án + Giải thích các bước giải:}$
`e//|x+(2)/(9)|=(7)/(10)`
`=>x+(2)/(9)=±(7)/(10)`
`=>` \(\left[ \begin{array}{l}x=\dfrac{7}{10}-\dfrac{2}{9}\\x=-\dfrac{7}{10}-\dfrac{2}{9}\end{array} \right.\)
`=>` \(\left[ \begin{array}{l}x=\dfrac{43}{90}\\x=-\dfrac{83}{90}\end{array} \right.\)
`\text{Vậy}` `x∈{(43)/(90);-(83)/(90)}`
`f//((2)/(9)-x)(x+(7)/(10))=0`
`<=>` \(\left[ \begin{array}{l}\dfrac{2}{9}-x=0\\x+\dfrac{7}{10}=0\end{array} \right.\)
`<=>` \(\left[ \begin{array}{l}x=\dfrac{2}{9}\\x=-\dfrac{7}{10}\end{array} \right.\)
`\text{Vậy}` `x∈{(2)/(9);-(7)/(10)}`
