Answer:
The answer is True
Explanation:
we know that
The function f(x) is a vertical parabola open downward
so
The equation of f(x) into vertex form is equal to

where
(h,k) is the vertex of the parabola
Let

Exchanges the variables x for y and y for x
Isolate the variable y
the coefficient a is negative

Let

------> inverse of the function f(x)
therefore
The inverse of f(x) is a function