The expression is .
(Commutative property of addition: )
(Add: )
(Product of two different signs is negative)
(Subtract: )
The sum is .
![\"\"](\"/userfiles/image/Library/Commutative_Property_of_addition.gif\")
![\"\"](\"http://www.mathskey.com/userfiles/image/steps_images/step1.JPG\")
![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=33d56978ca7ca8cd62d9c9e53fa45b19.png\")
.![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=5137fbf1f84781647e0e60a05fa954b9.png\")
(Commutative property of addition: ![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=04ab48db2a6385513b3391bf07d33cff.png\")
)![\"\"](\"http://www.mathskey.com/userfiles/image/steps_images/step2.JPG\")
![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=3aeb7c9a4e4f6cedf4a3ae602f76f9a4.png\")
(Add: ![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=62cc0ea2a536a54299225219f562c37a.png\")
)![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=e0cade69c0e2ecdf23a3c29f72724d95.png\")
(Product of two different signs is negative) ![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=962cee740d5fd9db1dfcb4ec34098e6a.png\")
(Subtract: ![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=886c0cf2a252b92e8df6039c26ebeaa8.png\")
)![\"\"](\"http://www.mathskey.com/userfiles/image/steps_images/solution.JPG\")
![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=d908a7df97ea85672a96fbfc88dc8b23.png\")
.