Write y=3x^2-6x+4 in vertex form. a, b,c, d ?

Let the closed interval [a , b] be the domain of function f. the domain of f(x - 3) is given by (a) the open interval (a , b) (b) the closed interval [a , b] (c) the closed interval [a - 3 , b - 3] (d) the closed interval [a + 3 , b + 3]

Idon't understand this at all! i would greatly appreciate all steps as to how you found the answer included in your explanation! !

The attendance at a seminar in year 1 was 500. in year two the attendance was changed by 100 what is the percent change in attendance? .2% .4% 20% 40%