We know that the polynomial function is of degree 3, and that its roots are -4, 0, 2.
With this data we can write a generic equation for the function:
f (x) = bx (x + 4) (x-2)
Since the function is of degree 3 and cuts the axis at x = 0, then it has rotational symmetry with respect to the origin.
The graph of the function can be of two main forms, based on the value of the coefficient b.
If b is positive then the function grows from y = -infinite and cuts the x-axis for the first time in -4. Then it decreases, cuts at x = 0 and begins to grow again cutting the x-axis for the third time at x = 2. and continues to grow until y = infnit
If b is negative, then the function decreases from y = infinity and cuts the x-axis for the first time in -4. Then it grows, cuts at x = 0 and begins to decrease again by cutting the x-axis for the third time at x = 2, and continues to decrease until y = -infnit.
In the attached images the graphs of the function f (x) are shown assuming b = -1 and b = 1
