![\"\"](\"http://www.mathskey.com/userfiles/image/steps_images/step1.JPG\")
Observe the graph,
\The blue color line passes through the points ![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=63cc318c90da9cced5f4fee2db5a79ce.png\")
and its slope is ![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=5adf26b3111823ea7ad56443177a8a31.png\")
.
The red color line passes through the points ![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=ce68009f2737aa245b843c89cea5dea0.png\")
and its slope is ![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=8ac8af567cdd6259a5e9c817d77de969.png\")
.
The green color line passes through the points ![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=2bbc9e57b088448408e19c4aae1e3fdd.png\")
and its slope is ![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=c336cfb7bb9901a4d763926faf1eb36f.png\")
.
The blue color line and green color line have the same slope, so they are parallel.![\"\"](\"http://www.mathskey.com/userfiles/image/steps_images/solution.JPG\")
The blue color and green color are parallel. \ \