Hannah wishes to find the vertex of the function x2 + 3x - 28 = 0 by completing the square. which of the following equations may be used to identify the coordinates of the vertex? a. (x + 1.2)2 = 30.25 b. (x + 2.25)2 = 30.5 c. (x + 2.5)2 = 30.75 d. (x + 2.75)2 = 32.5