Observe the graph, the two points are .
Substitute the values of in the slope formula .
.
The slope .
![\"\"](\"http://www.mathskey.com/userfiles/image/steps_images/step1.JPG\")
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.![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=c3069833a05c4b0f4cf0404756d470e5.png\")
in the slope formula ![\"\"](\"http://www.mathskey.com/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=e7702ef02c2ad62562856581dfb95519.png\")
.![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=4e6c0f34736d431df1f9ae2291635f59.png\")
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.![\"\"](\"http://www.mathskey.com/userfiles/image/steps_images/solution.JPG\")
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.