a: =>(x2-3)(2x2-5x-1)=0
=>\(x\in\left\{\sqrt{3};-\sqrt{3};\dfrac{5+\sqrt{33}}{4};\dfrac{5-\sqrt{33}}{4}\right\}\)
b: \(\Leftrightarrow\left(x^2+x-3\right)\left(3x^2-x-1\right)=0\)
hay \(x\in\left\{\dfrac{-1+\sqrt{13}}{2};\dfrac{-1-\sqrt{13}}{2};\dfrac{1+\sqrt{13}}{6};\dfrac{1-\sqrt{13}}{6}\right\}\)