Đáp án: $3x^2+4x-2=3(x+\dfrac{2-\sqrt[]{30}}{3})(x+\dfrac{2+\sqrt[]{30}}{3})$
Giải thích các bước giải:
$3x^2+4x-2=3(x^2+2x.\dfrac{2}{3}+\dfrac{4}{9})-\dfrac{10}{3}$
$\rightarrow 3x^2+4x-2=3(x+\dfrac{2}{3})^2-\dfrac{10}{3}$
$\rightarrow 3x^2+4x-2=3(x+\dfrac{2}{3}-\sqrt[]{\dfrac{10}{3}})(x+\dfrac{2}{3}+\sqrt[]{\dfrac{10}{3}})$
$\rightarrow 3x^2+4x-2=3(x+\dfrac{2-\sqrt[]{30}}{3})(x+\dfrac{2+\sqrt[]{30}}{3})$
