Data Table  A list of xvalues and their corresponding yvalues.
Negative Slope  y always decreases when x increases and y always increases when x decreases.
Ordered Pair  A pair of numbers in a specific order. For example, (3, 7) and (8,  1) are ordered pairs. Two ordered pairs are equivalent if their first members are equal and their second members are equal. However, the order of the two numbers is important; (1, 2) is not equivalent to (2, 1).
Origin  The point (0, 0).
Parallel Lines  Two lines are parallel if they have the same slope. Parallel lines, when extended, do not intersect at any point.
Perpendicular Lines  Two lines are perpendicular if their slopes are opposite reciprocals of each other. Perpendicular lines intersect each other at right angles.
Positive Slope  y always increases when x increases, and y always decreases when x decreases.
Slope  Given two points
(x_{1}, y_{1}) and
(x_{2}, y_{2}) on a line, the slope of the line is equal to:
m = 

xaxis  The horizontal axis of a graph, with which the xvalues are plotted.
xcoordinate  The number which corresponds to the value of x in an ordered pair.
xintercept  The point at which the graph of a line crosses the xaxis. The point at which y = 0.
xygraph  A twodimensional way of representing points.
xvalues are plotted with the horizontal axis, and
yvalues are plotted with the vertical axis.
xygraph
xygraph
yaxis  The vertical axis of a graph, with which the yvalues are plotted.
ycoordinate  The number which corresponds to the value of y in an ordered pair.
yintercept  The point at which the graph of a line crosses the yaxis. The point at which x = 0.