Ta thấy: \(\left|x-\frac{1}{2}\right|\ge0\forall x\in R\)
Để \(\left|x-\frac{1}{2}\right|+\frac{3}{4}\)đạt GTNN thì \(\left|x-\frac{1}{2}\right|\)có GTNN.
\(\Rightarrow\left|x-\frac{1}{2}\right|=0\Rightarrow x=\frac{1}{2}\)
Vậy \(x=\frac{1}{2}\)thì \(\left|x-\frac{1}{2}\right|+\frac{3}{4}\)có GTNN là \(\frac{3}{4}\).