Answer:
The function is negative for all real values of x where –6 < x < –2
Explanation:
we have

This function represent a quadratic equation (vertical parabola open upward)
The vertex represent a minimum
using a graphing tool
see the attached figure
The x-intercepts are x=-6 and x=-2
The y-intercept is the point (0,12)
The vertex is the point (-4,-4)
The domain is the interval -----> (-∞,∞) (All real numbers)
The range is the interval -----> [-4,∞) (All real numbers greater than or equal to -4)
The function is positive for x < -6 or x > -2
The function is negative for the interval (-6,-2) ----> –6 < x < –2
therefore
The function is negative for all real values of x where –6 < x < –2