f(x) = (1/2)x^2-x-(3/2) where a = 1/2, b = -1 and c = -3/2
The x coordinate of the vertex = -b/ [2a] = 1/[2(1/2)] = 1/1 = 1
And we can substitute back into f(x) to find the y value when x = 1
So, y = (1/2(1)^2 -(1) -(3/2) = (1/2) - (5/2) = -2
So the vertex is at (1. -2)
To get the zeros, set f(x) to 0 and we have
(1/2)x^2-x-(3/2) = 0 multiply through by 2
x^2 - 2x - 3 = 0 factor
(x - 3) (x + 1) = 0 and setting each factor to 0 we have that x = 3 and x = -1
In other words, the zeros occur at (3, 0) and ( -1, 0)
Here's the graph.......https://www.desmos.com/calculator/syjatyyvrk