Author:
Kyle Webb

In Algebra, you learned about linear equations and inequalities. Specifically, we can write the equation of a line if we have certain information: two points, a point and the slope, or the y-intercept and the slope. We have also learned three forms to use to write the equation of a line and when to use each form. We will review these forms of equations of lines as well as look at linear inequalities in this section.

Tutorial

Source: https://www.khanacademy.org/

How do you know if two lines are __parallel__?

**Their slopes are the same!**

How do you know if two lines are __perpendicular__?

**When you multiply their slopes, you get -1**

or** The slopes are multiplicative inverses**

or** The perpendicular slope is the negative reciprocal**

Source: http://patrickjmt.com/

Source: http://patrickjmt.com/