Post on 05-Jan-2016
Equations of Lines
Standard Form: cbyax
Slope Intercept Form: bmxy
where m is the slope and b is the y-intercept
Slopes of Lines
Given the points (x1, y1) and (x2, y2) on a line, its slope
is 12
12
xx
yym
If the slope is positive the line is increasing:
If the slope is negative the line is decreasing:
Slopes of Lines
Slopes of Lines
If the slope is zero the line is horizontal:
If the slope is undefined the line is vertical:
Slopes of Lines
21 mm
21
1
mm
If two lines are parallel their slopes are equal.
If two lines are perpendicular their slopes are negative reciprocals.
Graphing Lines
The x-intercept is the point where the line crosses the x-axis, found by setting y = 0 and solving for x.
The y-intercept is the point where the line crosses the y-axis, found by setting x = 0.