$3x^{}$ $^{2}$ + $5x^{}$ - $3^{}$ = $0^{}$
Δ = $b^{2}$ -$4.ac^{}$
= $5^{2}$ - $4.3.(-3)^{}$
= $25^{}$ - ($-36^{}$ )
= $25^{}$ + $36^{}$
= $61^{}$
⇒ $\sqrt[]{Δ}$ = $\sqrt[]{61}$
Vì $\sqrt[]{Δ}$ > 0 nên pt có 2 nghiệm phân biệt
⇒$x_{1}$ = $\frac{-b-$\sqrt[]{Δ}$ }{2a}$ =$\frac{-5-\sqrt[]{61}}{2.3}$ =$\frac{-5-\sqrt[]{61}}{6}$
$x_{2}$ = $\frac{-b+$\sqrt[]{Δ}$ }{2a}$ =$\frac{-5+\sqrt[]{61}}{2.3}$ =$\frac{-5+\sqrt[]{61}}{6}$
