5.3 Writing Linear Equations given Two Points
Objectives
SWBAT:
• Write the equation of a line given two points on the line
• Write the equation of line perpendicular to a given line
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Jan 16­1:24 PM
Finding Slope given 2 points
Slope of a line through 2 points (x , y ) and (x , y ):
2
2
1
1
m = rise = y ­ y
2
1
run x ­ x
2
1
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Writing a Linear Equation given 2 points
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Example 1
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Slope & perpendicular lines
Perpendicular lines: • Lines that intersect to form right angles
• Slopes are negative reciprocals of each other
Example: y = ¾ x + 2 y = ­4/3 x ­ 6
these lines are perpendicular
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Example 2 (Writing equations of perpendicular lines)
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Example 2 (solution)
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Practice & HW
• 288 ­ 289 # 2, 3 ­ 7, 9, 10, 17, 46
# 18, 20, 25, 29, 31, 37, 45, 47
p. 291 (Quiz 1) # 1 ­ 13
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