Observe the graph the line intersects at two points and .
Slope formula is .
(Substitute )
(Simplify)
The slope .
![\"\"](\"/userfiles/image/steps_images/step1.JPG\")
![\"open](\"http://www.wiris.com/portal/plugins/demo/fckeditor/php/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=a940b9ea418b9015a048b91749b85610.png\")
and ![\"open](\"http://www.wiris.com/portal/plugins/demo/fckeditor/php/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=a2a2d7b1707cd859f4e739a4baf61fbb.png\")
.![\"m](\"http://www.wiris.com/portal/plugins/demo/fckeditor/php/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=ad8d244cf5816b3df31ae916ebb6e83e.png\")
.![\"m](\"http://www.wiris.com/portal/plugins/demo/fckeditor/php/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=224e1b669a4e5700c4f7a63ba81cc244.png\")
(Substitute ![\"y](\"http://www.wiris.com/portal/plugins/demo/fckeditor/php/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=fb44544c846e350ae3958373fac420b1.png\")
)![\"m](\"http://www.wiris.com/portal/plugins/demo/fckeditor/php/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=bb19e5278387e0ddfe4d505b99cf55c2.png\")
(Simplify)![\"\"](\"/userfiles/image/steps_images/solution.JPG\")
.