Parallel and Perpendicular Lines

If two lines are perpendicular to each other their slopes are ____________

• the same.

• negative reciprocals of each other.

y = 5/7x +2

y = 5/7x - 30

These lines are...

• Parallel

• Perpendicular

• Neither

Write an equation for a line perpendicular to

y = -5x + 3 through (-5, -4)

• y = -3x + 1/5

• y = -3x - 1/5

• y = 1/5x - 3

• y = -1/5x - 3

Which is the equation of the line that is PARALLEL to the graph of y = 5x + 7 and has a y-intercept at (0, -2)?

HINT: PLUG (0,-2) AND THE PARALLEL SLOPE INTO y=mx+b. SOLVE FOR b AND REWRITE THE EQUATION IN y=mx+b.

• y = 5x - 2

• y = -2x + 7

• y = 5(x - 2)

• y = -1/5x - 2

Which of the following lines is PARALLEL to the graph of y = -6x + 3 and goes through the point (-1,4)?

HINT: PLUG (-1,4) AND THE PARALLEL SLOPE INTO y=mx+b. SOLVE FOR b AND REWRITE THE EQUATION IN y=mx+b.

• y=1/6x +25/6

• y = 1/6x + 4

• y = -6x - 2

• y = -6x + 4

Write an equation of a line that passes through the point (-9,2) and is perpendicular to the line y = 3x - 12

• y = (-1/3)x - 1

• y = (1/3)x - 2

• y = -3x + 12

• y = 3x - 1

Write the equation of a line PERPENDICULAR to y = -2x + 1 that passes through the point (2, 3).

Are these two lines parallel, perpendicular or neither?

y = -1/3x - 5

y = 1/3x + 2

• Parallel

• Perpendicular

• Neither

If two lines are parallel their slopes are  ____________

• the same.
• negative reciprocals of each other.