The expression is .
As denominators are same, write sum of numerators over denominator.
(Add numerator: )
The sum is .
![\"\"](\"http://www.mathskey.com/userfiles/image/steps_images/step1.JPG\")
![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=182eccc4f39daa464b9cf8ced838f48b.png\")
.![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=770950bc1e8b8a4d47645d557412975f.png\")
![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=039fc25c97190b5aae82f308d8019ea9.png\")
(Add numerator: ![\"\"](\"http://www.mathskey.com/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=402f8a925a16120281cefa9c74c8f449.png\")
)![\"\"](\"http://www.mathskey.com/userfiles/image/steps_images/solution.JPG\")
![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=2d48da053bfb77f1409152e3e1912ab2.png\")
.