Answer:
The function is increasing for all real values of x where
x < –4.
Step-by-step explanation:
we have
This is a vertical parabola open downward (the leading coefficient is negative)
The vertex (h,k) represent a maximum
The roots of the function (or x-intercepts) are x=-6 and x=-2
The x-coordinate of the vertex is the midpoint of the roots
so
The y-coordinate of the vertex is
substitute the x-coordinate of the vertex in the quadratic equation
The vertex is the point (-4,4)
The function is increasing in the interval (-∞,-4)
The function is decreasing in the interval (-4,∞)
