![\"\"](\"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=59c548d1e93a7a5e726eebbaf838f759.png\")
and its slope is ![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=1b83a364c6fc74552c6595408894d293.png\")
.
The red color line passes through the points ![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=8b4c4e15a4e9079ca01b6ab9638d1c43.png\")
and its slope is ![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=476c9fc0934590453487519dde8825ab.png\")
.
The green color line passes through the points ![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=19a90be84b891f2145a4d175c83e294d.png\")
and its slope is ![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=09db2e62710ea118680d359c5368c51f.png\")
.
The blue color line, red color and green color line have the same slope, so they are parallel.![\"\"](\"http://www.mathskey.com/userfiles/image/steps_images/solution.JPG\")
The blue, red and green color lines are parallel.