How long does it take for valium or xanax to be out of your system from the time you take them,:confused: thanks in advance for any feedback

Valium I know for a fact can stay in your urine for awhile I failed a drug screen 21 days after I stopped valium I finally passed my drug screen 26 days after stopping.so that's right at 4 weeks for valium . I heard xanax was much faster but I'm not sure