$3x^2 - 7x + 2 = 0$
$a=3,~b=-7,~c=2$
$r_1,r_2 = \dfrac{7\pm \sqrt{(-7)^2 - (4)(3)(2)}}{(2)(3)}$
$r_1,r_2 = \dfrac{7 \pm \sqrt{49 - 24}}{6}$
$r_1,r_2 = \dfrac{7 \pm \sqrt{25}}{6}$
$r_1,r_2 =\dfrac{7\pm 5}{6}$
$r_1,r_2 = \dfrac{12}{6},~\dfrac{2}{6}$
$r_1,r_2 = 2,~\dfrac 1 3$