Bell Work

Tell if data is linear. If so, write the equation.

1) 2) 3)x y-4 92 -35 -99 -

17

x y

-10 -5

-2 17

5 42

11 49

x y

3 1

6 4

9 13

15 49

Algebra 1

Parallel & Perpendicular Lines

School Day: 17 Objective: 2.02

Notes

Parallel lines are two lines that never intersect. They have the same slope.

Perpendicular lines are two lines that intersect to form right angles. They have negative reciprocal slopes.

(example: m = 2/3 and m = -3/2)

Examples

What is the negative reciprocal?

1) 2 2) -1/3 3) 4/5 4) -3/2

Examples

a) y = -2/3x + 7 b) y = -3/2x + 4c) y = 2/3x – 4 d) y = -2/3x – 2

5) Which lines are parallel?6) Which lines are perpendicular?

Examples

Write an equation in slope-intercept form that is parallel to the given line through the given point.

7) y = ½ x + 1 (4,2) 8) 2x + y = 5 (4,-6)

Examples

Write an equation in slope-intercept form that is perpendicular to the given line through the given point.

9) y = 1/6x – 1 (2,4) 10) 5x + 4y = 8 (10,5)

11) In Elmsville, Main St. has the equation 2y = 7x + 6. If First St. is parallel and

three streets up, what would be its equation?

12) In Coal City, Oak St. has the equation 3x + y = 4. If Elm St. is perpendicular

and two streets down, what would be its equation?