The expression is .
(The product of two different signs is negative)
(Multiply: )
(The product of two same signs is positive)
The product is .
![\"\"](\"../../../userfiles/image/steps_images/step1.JPG\")
![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=bce9301bd992c470464e1540e2a1651d.png\")
.![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=9a23da92e287ccd26bbea34224457891.png\")
(The product of two different signs is negative)![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=952f8bd867b28226ffb47a3346d2800d.png\")
(Multiply: ![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=dcf91e33984fb6c66fd1f2c28bb3a541.png\")
)![\"\"](\"../../../userfiles/image/steps_images/step2.JPG\")
![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=47140edccd946e3098425bed045c8590.png\")
(The product of two same signs is positive)![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=f0d3508450bbb1ff7bc644a8052bbad6.png\")
(Multiply: ![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=9c16ef3ad525d9e9d2c17bf733c4ee7c.png\")
)![\"\"](\"../../../userfiles/image/steps_images/solution.JPG\")
![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=4569c0dc533caf7a6ea4f3ecd70c34af.png\")
.