The expression is .
(Apply additive inverse property: )
(Apply additive identity property: )
The simplified expression is 9y.
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.![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=583cd5e5841b24fd4b4fcf5974fd6b28.png\")
(Apply additive inverse property: ![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=dcbc888ba1a88ca560f08c5119fb1c9c.png\")
)![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=1cbbf085d9bcd2aec7948be893c99fbc.png\")
(Apply additive identity property: ![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=b8d542e80ff8bf27512c3fa7f4ab6794.png\")
)![\"\"](\"/userfiles/image/steps_images/solution.JPG\")