Equations of Parallel and Perpendicular Lines

Front

Slopes of perpendicular lines are...

Back

negative reciprocals

Front

Slopes of parallel lines are...

Back

the same

Front

What is the slope of a line that is parallel to the line y = 2x + 3?

Back

2

Front

What is the slope of a line that is perpendicular to the line y = -1/2x + 4?

Back

2 (the negative reciprocal of -1/2 is 2)

Front

If two lines have slopes m1 and m2, and m1 * m2 = -1, what can we say about the lines?

Back

They are perpendicular.

Front

If two lines have the same slope, what can we say about them?

Back

They are parallel.

Front

What is the slope-intercept form of a line?

Back

y = mx + b, where m is the slope and b is the y-intercept.

Front

How do you find the slope between two points (x1, y1) and (x2, y2)?

Back

Slope (m) = (y2 - y1) / (x2 - x1).

Front

What is the slope of a horizontal line?

Back

0 (zero slope).

Front

What is the slope of a vertical line?

Back

Undefined.