$ \textbf{Answer:}$

$ x_1 = 0.753 , \ x_2 = -1.76$

$\textbf{Explanation:}$

We are going to use the quadratic formula $ x_1,x_2 = \frac{-b \pm \sqrt{b^2-4ac}}{2a}$ on $ 3x^2+3x-4=0$

where $ a= 3, \ b = 3 ,\ c=-4$

$ x_1, x_2 = \frac{-3 \pm \sqrt{3^2 -4(3)(-4)}}{2(3)}$

$ x_1, x_2 = \frac{-3 \pm \sqrt{57}}{6}$

$x_1 = \frac{-3+ \sqrt{57}}{6}$ and $ x_2 = \frac{-3- \sqrt{57}}{6}$

$ x_1 = 0.752$ and $x_2 = -1.76$