a) Vì `|x+5/6| >=0`
`<=> 2-|x+5/6|<=2`
`<=> A <=2`
Dấu "=" xảy ra `<=> x+5/6=0 <=> x=-5/6`
b) `|2/3-x| >=0`
`<=> 5-|2/3-x|<=5`
`<=> B<=5 <=> x=2/3`
a) Ta có: \(\left|x+\dfrac{5}{6}\right|\ge0\forall x\)
\(\Leftrightarrow-\left|x+\dfrac{5}{6}\right|\le0\forall x\)
\(\Leftrightarrow-\left|x+\dfrac{5}{6}\right|+2\le2\forall x\)
Dấu '=' xảy ra khi \(x=-\dfrac{5}{6}\)
b) Ta có: \(\left|\dfrac{2}{3}-x\right|\ge0\forall x\)
\(\Leftrightarrow-\left|\dfrac{2}{3}-x\right|\le0\forall x\)
\(\Leftrightarrow-\left|\dfrac{2}{3}-x\right|+5\le5\forall x\)
Dấu '=' xảy ra khi \(x=\dfrac{2}{3}\)
