Which of the following equations has the sum of its roots as 3?

We know that equation $a{x}^2+bx+c=0$

Then sum of roots $=\frac{-b}{a}$

(i) In equation $2x^2+3x+6=0$

the sum roots $=\frac{-3}{2}$ this not as3

(ii)IN equation $x^2-3x+3=0$

$\frac{-3}{1}=3$ this is 3

(iii) In equation $\sqrt{2}{x}^2+\frac{3}{\sqrt{2}}x=10\Rightarrow \sqrt{2}{x}^2+\frac{3}{\sqrt{2}}x-10=0$

Sum of roots $=\frac{-\frac{3}{\sqrt{2}}}{\sqrt{2}}=-\frac{3}{2}$ is not 3

(iv) In equation $3x^2+3x+3=0$

Sum of roots $=\frac{-3}{3}=-1$ This is not 3

Then in equation  $x^2-3x+3=0$ is 3