Take a vertical line and place it on thegraph<span>. </span>If<span> the </span>graph is a function<span>, then no matter where on the </span>graph<span> you place the vertical line, the </span>graph<span>should only cross the vertical line once.</span>
To find the domain of a graph observe the intervals of x that the line touches, and make an inequality of it. Same for the range but it's for the intervals of y. If the graph goes forever, then include "infinity" on the inequality
Answer:
-3.5
The distance Rachel covers per hour is 3.5 miles
Step-by-step explanation:
After 2 hours, she is 13 miles from the campground.
After 4 hours, she is 6 miles from the campground.
Let x be the number of hours, y be the number of miles from the campground, then we have two points (2,13) and (4,6).
The equation of the line passing through the points 
and 
is
Substitute:
Hence,
The slope of the line is 
and it represents that the distance Rachel covers per hour is 3.5 miles.
