\(8x^2\left(x^2-2.\frac{1}{4}x+\frac{1}{16}\right)+\frac{9}{2}\left(x^2-2.\frac{2}{9}x+\frac{4}{81}\right)+\frac{181}{36}\)
\(=8x^2\left(x+\frac{1}{4}\right)^2+\frac{9}{2}\left(x-\frac{2}{9}\right)^2+\frac{181}{36}>0\) \(\forall x\)
\(\Rightarrow\) Đa thức trên vô nghiệm