How to find the intervals that a function is increasing and decreasing

The video tutorial explains how to read a graph, focusing on identifying increasing and decreasing intervals based on X values. It emphasizes the importance of distinguishing between X and Y values when describing these intervals. The tutorial concludes with a summary of the graph's behavior, noting that it is not constant at any point.

Explain why we only consider X values when determining increasing or decreasing intervals.

Is there any point where the graph is constant? Justify your answer.