Two lines are if their are identical. For this exercise, we have been given two points on each line, so we have enough information to calculate their slopes using the .
Note that when choosing points to substitute for
it doesn't matter which points on the line you choose, since the result will be the same. Let's start with line
which passes through
Thus, the slope of line
is equal to
We will use the same method to calculate the slopes of lines
Now that we've identified the slope of each line, we can see that line and have the same slope but not line Therefore, the three lines are not all parallel.