\
The expression is
Square Root of a Number: If b2 =a, then b is a square root of a.
The positive and negative square roots of 169 are 13 and -13.
The value of the expression is .
![\"\"](\"/userfiles/image/steps_images/step1.JPG\")
![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=f1b5958df3c91cfde4121481ce01db0a.png\")
![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=ec4015bb3565c9ec530d514ed276a690.png\")
![\"\"](\"/userfiles/image/steps_images/solution.JPG\")
![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=af92cdaddbe8888af291c19e83d5094a.png\")
.