The expression is .
(Commutative property of addition: a + b = b + a)
(Add: )
= 0 (Additive inverse property:)
The sum is 0.
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(Commutative property of addition: a + b = b + a)![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=eda065967c437ee30d30f392aba45486.png\")
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