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Step-by-step explanation:
Vertex form of a quadratic can be written as ...
a(x -h)² +k = 0 . . . . . . vertex (h, k); scale factor 'a'
First of all, it highlights the vertex (x, y) = (h, k), which is the extreme maximum or minimum of the function. That also tells you the axis of symmetry, (x = h).
Vertex form also shows you the vertical scale factor. The sign of that tells you whether the graph opens upward (positive) or downward (negative). The numerical value of it tells you the vertical distance from the vertex to points ±1 unit either side of the vertex.
The roots of the quadratic will be ...
x = h ±√(-k/a)
These will be complex if the graph does not intersect the x-axis.