Answer:
First, we know that the 0 in the horizontal axis corresponds to the noon.
Then:
a) Lin's elevation at noon in meters.
We need to see the elevation when x = 0.
This is the point that is just on top of the y-axis, we can see that when x = 0, we have y = 6.
Then at noon, her altitude was 6 meters.
b) At 8:00 am, her elevation was 2m
Remember that the x-component represents time, and x = 0 represents the noon.
8:00 am is 4 hours before noon, then 8:00am is represented with x = -4
and at this time her elevation is 2m, then y = 2.
This means that the point that represents this is (-4, 2)
c) At 4:00 pm Lin was at sea level (her elevation was 0m)
Same reasoning than before: x = 0 is the noon, then 4:00 pm is four hours after this, then 4:00 pm is represented with x = 4.
And here her altitude is 0m, then y = 0.
This point is written as (4, 0)
d) Here we can see that at 6:00 am her elevation was negative, and at 4:00pm her elevation is 0.
And we know that:
0 > negative numbers.
Then her altitude increased in this interval of time.
