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Example 3 Graph Parallel and Perpendicular Lines
a. Draw the graph y 5 2x 2 3.
b. Graph the line that passes through (0, 2) and is
parallel to the graph of y 5 2x 2 3.
c. Graph the line that passes through (0, 2) and is
perpendicular to the graph of y 5 2x 2 3.
Solution
a. Draw the graph y 5 2x 2 3
using the y-intercept 23 and
slope 2 .
b. Graph the point (0, 2). Any
line parallel to the graph of
y 5 2x 2 3 has the same
slope, 2 . From (0, 2), move
up 2 units and right
1 unit. Plot a second point at (1, 4) . Draw a line
through the two points.
c. The slope of any line perpendicular to the
graph of y 5 2x 2 3 is the negative reciprocal
of 2, or 2 1
} . So, from (0, 2), move down 1 unit
2
and right 2 units. Plot a second point at
(2, 1) . Draw the line.
Checkpoint On the same grid, draw each graph.
1. y 5 2 1 }
3 x 1 1
2. The line parallel to
y 5 2 1 }
3 x 1 1 through
the point (0, 4)
3. The line perpendicular
to y 5 2 1 }
3 x 1 1 through
the point (0, 4)
36 Lesson 2.4 • Algebra 2 C&S Notetaking Guide Copyright © McDougal Littell/Houghton Mifflin Company
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