Notes with answers - Summit Schools

Your Notes
Example 2 Classify Lines Using Slope
Without graphing, tell whether the line through the
given points rises, falls, is horizontal, or is vertical.
a. (26, 22), (1, 3) b. (2, 21), (2, 2)
Solution
a. m 5
b. m 5
3 2 (22)
}
1 2 (26)
2 2 (21)
}
2 2 2
5 5
}
7 Because m > 0, the line rises .
5 3
}
0 Because m is undefined , the
line is vertical .
Checkpoint Complete the following exercises.
1. Find the slope of the line through (4, 2) and (7, 9).
7
}
3
2. Without graphing, tell whether the line through the
points (23, 2) and (1, 4) rises, falls, is horizontal, or
is vertical.
rises
Example 3 Compare Steepness of Lines
Tell which line is steeper.
Line 1: through (2, 3) and (21, 4)
Line 2: through (27, 22) and (24, 25)
Solution
Slope of line 1: m 5
Slope of line 2: m 5
4 2 3
}
21 2 2
25 2 (22)
}
24 2 (27)
5 1
}
23
or 2 1
}
3
5 23
}
3
5 21
Both lines have negative slope.
Because |m1 | > |m2 |, line 1 is steeper than
line 2 .
Copyright © McDougal Littell/Houghton Mifflin Company Lesson 2.3 • Algebra 2 C&S Notetaking Guide 31