Which of the following equations has the sum of its roots as 3?
2x2-3x+6=0
-x2+3x-3=0
3x2-3x+3=0
x2+5x+6=0
(a) x2 + 3x − 5 = 0 (b) −x2 + 3x + 3 = 0
(c) (d) 3x2 − 3x − 3 = 0