Ta có; $PT\Leftrightarrow (x-1)(\sqrt{2x^{2}-5x-15}-2)+\sqrt{\frac{2x^{3}-7x^{2}+19}{2}}-\sqrt{7x}=2x^{3}-7x^{2}-14x+19\Leftrightarrow (2x^{3}-7x^{2}-14x+19)(\frac{1}{\sqrt{2x^{2}-5x-15}+2}+\frac{1}{2(\sqrt{\frac{2x^{3}-7x^{2}+19}{2}}+\sqrt{7x})}-1)=0$
vì dễ có: $\frac{1}{\sqrt{2x^{2}-5x-15}+2}+\frac{1}{2(\sqrt{\frac{2x^{3}-7x^{2}+19}{2}}+\sqrt{7x})}-1< \frac{1}{2}+\frac{1}{2}-1=0\Rightarrow PT\Leftrightarrow 2x^{3}-7x^{2}-14x+19=0\Leftrightarrow x=1;x=\frac{5+\sqrt{177}}{4};x=\frac{5-\sqrt{177}}{4}$
làm nhanh thế, t bấm ra mỗi 1 nghiệm