Answer :
n-the number
[tex]\dfrac{1}{3}n=n-12\ \ \ \ |multiply\ both\ sides\ by\ 3\\\\n=3n-36\ \ \ \ \ |subtract\ 3n\ from\ both\ sides\\\\-2n=-36\ \ \ \ \ |divide\ both\ sides\ by\ (-2)\\\\n=18[/tex]
[tex]\dfrac{1}{3}n=n-12\ \ \ \ |multiply\ both\ sides\ by\ 3\\\\n=3n-36\ \ \ \ \ |subtract\ 3n\ from\ both\ sides\\\\-2n=-36\ \ \ \ \ |divide\ both\ sides\ by\ (-2)\\\\n=18[/tex]