Parallel and Perpendicular Lines

How Do You Find the Slope of a Line If You Have a Perpendicular Line?

Perpendicular lines have slopes that are opposite reciprocals of each other. To find the slope of a line that is perpendicular to a given equation, find the opposite reciprocal of that slope. Check out this tutorial to learn how!
How Do You Know if Two Lines are Parallel?

Parallel lines are lines that will go on and on forever without ever intersecting. This is because they have the same slope! If you have two linear equations that have the same slope but different y-intercepts, then those lines are parallel to one another!
How Do You Know if Two Lines Are Perpendicular?

Perpendicular lines intersect at right angles to one another. To figure out if two equations are perpendicular, take a look at their slopes. The slopes of perpendicular lines are opposite reciprocals of each other. Their product is -1! Watch this tutorial and see how to determine if two equations are perpendicular.