When writing an equation for a perpendicular line, there are some things that you need to remember. First, remember that lines that are perpendicular have slopes that are negative reciprocals. Perpendicular lines should always form a right angle. So, if they don’t form a right angle you know something is incorrect.

When writing an equation for parallel lines, you need to know that the parallel lines have the same slope. Parallel lines have to have different y-intercepts in order to be parallel. Any two vertical lines are parallel.

When we learned Lesson 6–2, we found it helpful to know these vocabulary terms:

 

Linear Function- A function that graphs a line

Parent Function- The simplest equation of a function

Linear Parent Function- The equation y = x or f(x) = x

Linear Equation- An equation that models a linear function

y‐intercept- y‐coordinate of the point where a line crosses the y‐axis

Slope‐Intercept Form- y = mx + b