Graphing Lines

Vocabulary

linear equation in two variables

equation in two variables whose graph is a line

parallel lines

lines in the same plane that do not intersect

perpendicular lines

lines that intersect at a 90° angle

point-slope form of a line

linear equation, where mm is the slope and (x1,y1)(x_1, y_1) is a point on the line, expressed as:
yy1=m(xx1)y-y_1=m(x-x_1)

rise

vertical change between two points on a line

run

horizontal change between two points on a line

slope

ratio of the change in yy to the change in xx for two points on a line, represented as:
RiseRun\frac{\text{Rise}}{\text{Run}}

slope-intercept form of a line

linear equation, where mm is the slope and bb is the yy-intercept of the line, expressed as:
y=mx+by=mx+b

standard form of a line

linear equation, where AA, BB, and CC are integers, AA is nonnegative, and AA and BB are both not zero, expressed as:
Ax+By=CAx+By=C

x-intercept

value of xx where a graph touches or crosses the xx-axis

y-intercept

value of yy where a graph touches or crosses the yy-axis