Unsure of what you are asking!
But if the issue here is how to define a line segment, write what you do know and then reconsider "undefined terms."
A line segment is a straight line that connects a given starting point and given ending point.
If you consider a circle of radius 3 units, the radius can be thought of as the line segment connecting the center of the circle to any point on the circumference of the circle.
If the center of a given circle is at C(0,0) and a point on the circumference is given by R(3sqrt(2),3sqrt(2)), then AC is the line segment joining these two points. This line segment has length 3 and is in the first quadrant, with coordinates x=3sqrt(2) and y=3sqrt(2) describing the end point of the segment.
Substitute -3 to x
(-3)^2 + 4(-3) + 1
9 - 12 + 1
= -2
1. No correlation
Those things don't really relate to each other.
2. Positive correlation
The more you drive your car, the more you'll have to pay for gas.
3. Negative correlation
More people = less soda.
