The expression is .
(Substitute )
(Product of two same signs is positive)
(Multiply: )
(Add: )
The solution is .
![\"\"](\"http://www.mathskey.com/userfiles/image/steps_images/step1.JPG\")
![\"\"](\"http://www.mathskey.com/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=09d806d6a534e9053dc52dc21b3109da.png\")
.![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=df308f65d22a12317ce9e34659e5e9b4.png\")
(Substitute ![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=f544f67b9ed6c9575ca6f8e66dfdd128.png\")
)![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=a21e2d8f256e751dd4d3af68d278ebfc.png\")
(Product of two same signs is positive)![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=c457356e8a638540686acd5ad5c0e766.png\")
(Multiply: ![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=43d1511231521aa14e5dab0a6bebc1ac.png\")
)![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=afa4690d1791e4f81bce992b4109e7a3.png\")
(Add: ![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=674e3557299c4dce637ed62dce64f813.png\")
)![\"\"](\"http://www.mathskey.com/userfiles/image/steps_images/solution.JPG\")
![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=dee29bf67b05589babbf57803b4d65e3.png\")
.