Step-by-step explanation:
You need a arbitrary points that will help you determine the sketch of the graph. I say use at most 5 points but you just need to know the following
The exterma: The maximum/minimum points on a certain interval.
The zeroes: What values willTheorem, Factoring, and more to help you find the zeroes.
Increasing and decreasing behavior between the consective zeroes: How the function behaves around consective zeroes. It must be above or below x axis between the zeroes.
And finally, the end behavoir: How the function behaves as x approaches infinity and negative infinity. Does the function increases or decreases.
That it. If you need an example, just ask me