Question

Consider the function shown.

Where is the function decreasing?
Enter your answer in the boxes.

The function is decreasing from x =___ to x =___ .

Answer 1

We say that a function decreases, when while x-values increases, y-values decreases.

We say that a function increases when while x-values increases, y-values decreases.

Also, graphically, if the line has a positive slope, that is, is inclined to the right, then the function is increasing in that interval. If the line is inclined to the left, then the function is decreasing in that interval.

So, in the graph we observe that:

From x=-5 to x=-2, the function increases.

From x=-5 to x=1, the function doesn't increases or decreases.

From x=1 to x=8, the function decreases.

Answer 2

Just by seeing the graph, we can see that the function is decreasing from

x = 1 , to x = 8

(In this section the function has negative slope, its rate of change is negative)
(From x = -5 to x = -2 the function is increasing)
(From x = -2 to x = 1 the function stays the same)