Depending on the extent of the damage, it may be possible to put them back in with a very small amount of Epoxy. However, the supporting plastic MUST be intact. If it's intact without further damage, it's a good candidate for this repair. This is not a pro quality fix and should not be used as such, but it’s not bad for a home user with this problem wanting to try it.
The problem is many of these fail in a way that's beyond repair without a new back cover. More often then not the plastic around the anchor on the chassis fails in a unrepairable fashion and that's the end of it. If you can fix it, Epoxy isn’t hard to find and is cheap. To know with 100% certainty it’s sold, check a hardware store like Lowes and Home Depot first. If you can't find it there (or do not live near one), buy some on Amazon. Either way, get gloves. Epoxy DOES NOT COME OFF OF SKIN and you have to wait until skin cells die to get rid of it. You only have one shot, so be very conservative; no more then needed and keep it away from the screw hole.
I am going to assume you know how to take the laptop apart, since you have access to these broken anchor points. Once you have access, put a screw in a very, very small amount for grip (Epoxy is a bear to get off skin) and then spread it on the sides with a toothpick. Put them in and then immediately remove the screw. Do this with all of the failed anchor points and it will be like new again. It may not last, but this often works to save a repairable chassis that has minor damage, at the most.