Let‘s start with the first part: What do these words mean for a function:
INCREASING: A function or its graph is increasing if it is „going up“, increasing in its y value while the x value increases.
DECREASING: A function or its graph is decreasing if it is „going down“, decreasing in its y value while the x value increases.
CONSTANT: A function is constant when it is horizontal, meaning it stays at the same y value while the x value increases.
Do you think you can work out the rest of the problem by yourself? Else let me know :)