The function regarding the length of the pencil (in) with respect to the time it is sharpened in seconds is not linear. The graph below in the screenshot shows that the function is not linear.
Work Step by Step
The function is not linear because if you look at the graph, it shows that the length of the pencil is decreasing exponentially because the graph decreases by 0.1 in after 12 minutes and then decreases 0.1 in more after only 3 minutes. There is no constant decrease in the length of the pencil after sharpening the pencil for a certain time.