Algebra
SLOPES
Since slope m is a measure of the steepness of a line, a slope has the following characteristics:
1.
A horizontal line has zero slope.
2.
A line that rises to the right has positive slope.
3.
A line rising to the left has negative slope.
4.
A vertical line has undefined slope because the calculation of the slope would
involve division by zero. (
approaches infinity as the slope approaches
Dy/Dx
vertical.)
Example:
What is the slope of the line passing through the points (20, 85) and (30, 125)?
Solution:
m
125
85
30
20
40
10
4
Given the coordinates of the y-intercept where the line crosses the y-axis [written (0, y)] and the
equation of the line, determine the slope of the line.
The standard linear equation form is y = mx + b. If an equation is given in this standard form,
m is the slope and b is the y coordinate for the y-intercept.
Example:
Determine the slope of the line whose equation is y = 2x + 3 and whose
y-intercept is (0,3).
Solution:
y = mx + b
y = 2x + 3
m = 2
Rev. 0
Page 87
MA-02
