"9. If a is a non-zero constant, determine the vertex of the function y = -x2 + 4ax + 3 in terms of a. A) (2a, 4a2 + 3) B) (-2a, 12a2 + 3) C) (a, 3a2 + 3) D) (-a, -5a2 + 3) E) None of these
a -> - 1 ; b -> 4a ; c -> 3 ; x = -b / (2a ) ; x = -4a / ( - 2 ) ; x = 2a ; y = -(2a)^2 + (4a)×(2a) + 3 ; y = -(4a^2) + 8a^2 + 3 ; y = 4a^2 + 3 ; The vertex of the function is ( 2a ; 4a^2 + 3 ) A).
