writing equations of parallel and perpendicular lines

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Writing equations of parallel and perpendicular lines

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Page 1: Writing equations of parallel and perpendicular lines

Writing equations of parallel and

perpendicular lines

Page 2: Writing equations of parallel and perpendicular lines

X

Y

Y = ½X + 6

Y = -²/₁X + 0

Y = ½X - 4

Parallel lines ALWAYS have the same slope

Perpendicular lines have OPPOSITE RECIPROCAL slopes

Page 3: Writing equations of parallel and perpendicular lines

Write the equation of the line that goes through point (-3, -5) and is parallel to the line Y = 3X - 1

Y = mX + bx y m

-5 = (3)(-3) + b-5 = -9 + b

+9+94 = b

Y = 3X + 4

Page 4: Writing equations of parallel and perpendicular lines

Write the equation of the line that goes through point (4, -5) and is perpendicular to the line Y = 2X + 3

Y = mX + bx y m

-5 = (-½)(4) + b-5 = -2 + b

+2+2-3 = b

Y = -½X - 3

Page 5: Writing equations of parallel and perpendicular lines

Determine which lines if any are parallel or perpendicular a) 2X + 6Y = -3 b) Y + 8 = 3X c) -15Y + 45X = 60

-2X-2X

6Y = -3 – 2X6 6

-3 6

- 2X 6

-1 1 2 3

- X

- 8- 8

Y = 3X - 8-45X

-45X

-15Y = 60 – 45X-15 -15

60-15

45X-15

-

Y = -⅓X - ½

-4 3 1 1

+ X

Y = 3X - 4

Parallel lines are… b and c

Perpendicular lines are… a and b a and c