The equation of the function is −3<x<1. See the explanation below.
Given the graph of function f is a parabola,
Thus, equation of parabola is y=(x+3)(x+1)
⇒y=x² +4x+3
⇒y−3+2²
= x²+2× x ×2+2²
⇒y+1=(x+2)²
We can rewrite this as
(x+2)² =4× (1/4) ×(y+1)
Comparing the above equation to the equation of a parabola, (x−h)² =4a(y−k), where (h,k) is the coordinates of vertex of parabola, we have,
(h,k)≡(−2,−1)
Hence, the x coordinate of the vertex is −2 which lies in the interval −3<x<1
Learn more about functions at;
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