i really need help with this 2 exercises i don't know where to start can someone explain and show your work please pleaseee

Graph the function =gx+2x3 and give its domain and range using interval notation.

How do you solve questions 29 and 31?

The change in water level of a lake is modeled by a polynomial function, w(x). described how to find the x-intercepts of w(x) and how to construct a rough graph of w(x) so that the parks department can predict when there will be no chage in the water level. you may create a sample polynomial of degree 3 or higher to use in your explanations.