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The expression is .
(Associative property: (a + b) + c = a + (b + c))
(Distributive property: a (b + c) = ab + ac)
(Add: 5 + 7 = 12)
The simplified expression is .
![\"\"](\"/userfiles/image/steps_images/step1.JPG\")
![\"\"](\"/MathKey/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=06b2e84c104a343ad2a2567a5d1c1954.png\")
.![\"\"](\"/MathKey/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=1ec454df4d98940745b65aa461f8fc48.png\")
(Associative property: (a + b) + c = a + (b + c))![\"\"](\"/MathKey/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=b0486baa9a7aa03af27ab787b4f18703.png\")
(Distributive property: a (b + c) = ab + ac) ![\"\"](\"/MathKey/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=0070a4cbd49d31e3cadb907dd9dd87e9.png\")
(Add: 5 + 7 = 12) ![\"\"](\"/userfiles/image/steps_images/solution.JPG\")
![\"\"](\"/MathKey/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=26f8f44dc1868898b5ff8001652edeae.png\")
.