The two line equations are adjusted in the slope - intercept form of equations or .
To tell the two lines are perpendicular, the two lines in the same plane have slopes are negative reciprocals.
![\"\"](\"http://www.mathskey.com/userfiles/image/steps_images/solution.JPG\")
![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=37a3162ea0616fe6c23aa6e01e176309.png\")
.