floor tiles cracking

I'm trying to restore our floor tiles which were hidden away under a laminate floor and stick on vinyl. We've done a decent job cleaning up the tiles but have a question regarding which kind of sealant is better for these type of tiles. see pictures I've also got some cracks and gaps in the...

Hi, several floor tiles have cracked at the edge where it meets the carpet. Ive chipped them off to replace them and found the tiled area has been plyboarded. theres a bit of movement when you stand on the edge im guessing thats why they cracked. Im planning on ising flexible tike adhesive ...