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Big Ideas Math Algebra 1, 2015

BI

Big Ideas Math Algebra 1, 2015 View details

3. Writing Equations of Parallel and Perpendicular Lines

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Exercise 18 Page 191

Parallel lines have the same slope. The slopes of perpendicular lines, however, are negative reciprocals.

Parallel or Perpendicular Lines: None of the lines are parallel. Lines $a$ and $b$ are perpendicular.
Explanation: See solution.

Practice makes perfect

Two lines are parallel if their slopes are identical. To tell if two lines are perpendicular, we check if their slopes are negative reciprocals. Let's tackle these one at a time.

Are They Parallel?

We will write each equation in slope-intercept form. Let's start with line

a .

y = 6 x - 2

Since it is already in the Slope-Intercept Form, we can conclude that the slope of the line

a

is

6 .

Now, let's take a look at the line

b .

Subchapter links

Communicate Your Answer p.187

Monitoring Progress p.188-190