For a graph with f(x)=x^2, the vertex of the parabola is at the origin.
In the given graph, the parabola is shifted 3 units to the left and 1 unit down.
The general vertex form of a parabola is,

Here, h is the horizontal shift and k is the vertical shift.
Since the graph is only translated and not shrinked or expanded , a=1.
Since the graph is shifted horizonatlly to the left, h is negative.
So, h=-3.
Since the graph is shifted vertically down, k is negative.
So, k=-1.
So, the equation for the given graph becomes,
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Therefore, the function in vertex form is,
