\(A=\left|x+3\right|+1\ge1\forall x\)
Dấu '=' xảy ra khi x=-3
\(B=-\left|2x-1\right|+3\ge3\forall x\)
Dấu '=' xảy ra khi \(x=\dfrac{1}{2}\)
\(A=\left|x+3\right|+1\) (GTNN)
Vì \(\left|x+3\right|\ge0\) nên \(\left|x+3\right|+1\ge1\) hay \(A\ge1\)
Dấu ''='' xảy ra khi x=-3
\(B=-\left|2x+1\right|+3\) (GTLN)
Vì \(\left|2x+1\right|\ge0\) nên \(-\left|2x+1\right|+3\le3\) hay \(B\le3\)
Dấu ''='' xảy ra khi x=\(\dfrac{-1}{2}\)