You can't from Comcast. Maybe in your router's log entries.
thanks , I have this entry on my event log on my modem
[Dhcpc]: erouter0 got new IP 73.yyy..xxx..35 2020/2/11 02:18:36 Notice
and it sync with the System uptime,, does this mean , this IP was assiged on 2/11/2020 ?
Looks like it.
Quite welcome !