The expression is .
(Commutative property of addition: )
(Product of two different signs is negative)
(Subtract: )
(Add: )
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=2b3e0c6084a7508017189802637183a8.png\")
.![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=a246ca47dc7d87bfcb688c86fd156352.png\")
(Commutative property of addition: ![\"\"](\"http://www.mathskey.com/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=872c07b058e4a332bb8d218006f887d0.png\")
(Product of two different signs is negative) ![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=bbb752f4f8178f5d4218d5651223e899.png\")
(Subtract: ![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=4cb3aa4853733c1d00e8f5aa1070fd39.png\")
)![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=b1102c512d48a5772a60d80e0a43b697.png\")
(Add: ![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=b6ad04437f8cd1421a16ac8911050177.png\")
)![\"\"](\"http://www.mathskey.com/userfiles/image/steps_images/solution.JPG\")
![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=3d39b68cd526a22097890cc682008fd4.png\")
.