7.1.4 & 7.1.5
Thursday, March 07, 2013
9:08 AM
Assignment: # 31 - 40, 43 - 45, 48
Slope of a Line
Slope is a measure of the steepness of a line. It is
the ratio of the vertical distance to the horizontal
distance of a slope triangle. The vertical part of the
triangle is called Δy ("change in y") while the
horizontal part of the triangle is called Δx ("change
in x").
Slope triangles must be drawn from two
"lattice points" or from where two graph
paper lines intersect and must be drawn
on the grid paper lines
Some common errors are shown below:
Chapter 7 Page 1
Graphing
using x & y
Intercepts
The x-intercept of a line
is the point where the graph
crosses the x -axis. The
coordinates of the x-intercept
are (x, 0). To find the x-intercept,
substitute 0 for y and solve for x.
The y-intercept of a line is
the point where the graph
crosses the y-axis. The coordinates
of the y-intercept are (0, y). To find the y-intercept,
substitute 0 for x and solve for y.
Example:
Find the x & y intercepts of the line 2x - 5y = 10.
This method can also be used to graph equations in
standard form (ax + by = c).
Chapter 7 Page 2
standard form (ax + by = c).
Examples:
1) Find the x- & y- intercepts of the equation 4x - 3y = -24
2) Find the x- & y- intercepts of the equation -5x + 2y = 10
3) Find the x- & y- intercepts of the equation -3x + 5y = -30
31)
Chapter 7 Page 3
32)
33.
37)
Chapter 7 Page 4
37)
43)
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Chapter 7 Page 5
45. Finding the slope of a line WITHOUT graphing
Chapter 7 Page 6