- The domain is what x values can exist on a curve, or graph; the y for range. In this case, the domain is restricted, given another condition, to essentially a list of x-values, namely -5, 0 and 1. Note that on the function you have mentioned can exist anywhere in x normally, and hence anywhere in y such that the relationship between the two holds, as it is one-to-one and has no discontinuities and asymptotes; basically anywhere x or y cannot exist, but is restricted as an extra condition. Going back to the one-to-one point; this means one x-value to one y-value, or every x has a unique y. So in this case, all we have to do is plug in the x-value into the function to find it’s unique y-value. That being 2, -2 and -2 and 4/5 going from left to right.
The difference between your speed is 6 miles per hour: that means that every hour you move 6 miles relative to your friend. But you only need to catch up 3 miles: half of it. So you'll catch up after 30 minutes.
