Is it safe to just unscrew the nut that connects a pex pipe directly with a tap?

[abe]

I tried to replace a couple of taps but surprisingly they are screwed directly to the pex piping instead to the flexible tap connectors.

I'm no expert so I don't know if I can proceed as normal. I'm hesitant to just unscrew the nut because it looks like a permanent fitting glued to the pex and I don't want to break the seal without the needed materials.

I really appreciate any idea to move forward. Thank you so much!

Other details:

Those pipes does not have isolation valves. I don't have cement / special glue for pex just now.. Do I need some?

I'm changing the taps because they are in very bad shape with broken plastic nuts at the bottom, so each time I use them I stress the pex pipes because they need much more force than normal in order to stop the water.

English is not my first language. I hope I didn't say anything stupid, just in case, I'm really sorry .

 

[Aquarius]

They look like grey hep20 push fit, the nut will unscrew and reveal either a rubber or fibre washer. So no solvent cement required.

 

[abe]

They look like grey hep20 push fit, the nut will unscrew and reveal either a rubber or fibre washer. So no solvent cement required.

Thank you so much Aquarius for the advice It was really helpful, now I'm more confident to do it!
I wouldn't have doubted so much if the connector was like this one:

 

[Aquarius]

Abe, it's very similar, obviously don't forget to turn the water off and drain before starting.

 

[abe]

Abe, it's very similar, obviously don't forget to turn the water off and drain before starting.

Abe, it's very similar, obviously don't forget to turn the water off and drain before starting.

It was as you said, all went super easy. Thank you again Aquarius for your time and help, it really made a difference.