![\"\"](\"http://www.mathskey.com/userfiles/image/steps_images/step1.JPG\")
\
Least common denominator (LCD) of two fractions is the least common
\multiple (LCM) of the denominators.
\To find the LCD first find the LCM of the denominators.
\Write the prime factorization of each denominator.
\![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=fa39be7197283b4a58103abf0d94078e.png\")
![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=7bcf70e004f0bc3d7f618f437b87ac6c.png\")
![\"\"](\"http://www.mathskey.com/userfiles/image/steps_images/step2.JPG\")
Write the each prime factorization in the exponential form.
\![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=0b94ede4408ca0ca2a3f87c8d08ec9a1.png\")
![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=5b17bb2faa025f417bb61092e90c8ef5.png\")
![\"\"](\"http://www.mathskey.com/userfiles/image/steps_images/step3.JPG\")
Multiply the highest power of each factor in either denominator.
\![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=a141e4977bd773ba06d807f3edae1849.png\")
![\"\"](\"http://www.mathskey.com/userfiles/image/steps_images/solution.JPG\")
Least common denominator (LCD) of the given fractions is 21. \ \