[tex] -3x^2+10x+12=0\\
\Delta=10^2-4\cdot(-3)\cdot12=100+144=244\\
\sqrt{\Delta}=\sqrt{244}=2\sqrt{61}\\
x_1=\dfrac{-10-2\sqrt{61}}{2\cdot(-3)}=\dfrac{-10-2\sqrt{61}}{-6}=\dfrac{5+\sqrt{61}}{3}\\
x_2=\dfrac{-10+2\sqrt{61}}{2\cdot(-3)}=\dfrac{-10+2\sqrt{61}}{-6}=\dfrac{5-\sqrt{61}}{3}\\[/tex]