Key Terms
EXAMPLE
Y = -3x - 4
CARTESIAN COORDINATE SYSTEM
A two-dimensional grid with perpendicular axes (x horizontal, y vertical); also called the rectangular coordinate system
ORDERED PAIR
A pair (x, y) representing a point's horizontal and vertical displacement from the origin.
ORIGIN
The point (0, 0) where the two axes cross.
QUADRANT
One of the four sections the axes divide the plane into, numbered I through IV counterclockwise starting from the upper
DISTANCE FORMULA
D = sqrt( (x2 - x1)^2 + (y2 - y1)^2 ); derived from the Pythagorean Theorem; gives straight-line distance between two po
MIDPOINT FORMULA
M = ( (x1 + x2)/2 , (y1 + y2)/2 ); gives the point exactly halfway between two endpoints.
INTERCEPTS
Points where a graph crosses the axes. x-intercept has y = 0; y-intercept has x = 0.
EQUATION IN TWO VARIABLES
An equation with both x and y; its solution is a set of ordered pairs, not a single number.