Substitute in slope formula.
or undefined. \ \
The slope of the line that passes through the points is "undefined".
![\"\"](\"http://www.mathskey.com/userfiles/image/steps_images/step1.JPG\")
![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=12eb72bc193b3be06bae633946402a76.png\")
in slope formula.![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=305894c2a42368aee04a2c333d902d5f.png\")
![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=96ffd22e7aaab91736281f6eb4250fcb.png\")
![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=1d47b94f9b75c54a979f8f79b359cd23.png\")
or undefined. \ \
![\"\"](\"http://www.mathskey.com/userfiles/image/steps_images/solution.JPG\")