is it generally ok to trade knight+bishop vs rook+pawn?

I am a beginner in chess and I have often the opportunity to use the typical bishop+knight against the f7 pawn, with the knight already castled. If I take with the bishop the adversary typically captures my bishop with the rook, i capture it with my knight and finally the king captures my knight. For me it’s cool because the opoonent king is not that safe and the opponent loses a rook, but a friend said me he prefer to have the bishop and the knight.

Do you think, generally speaking, it is worth to do this trade?

I don't think it's a recommended approach at all. Chances are you've set this up very early on in the game when your bishop and Knight should be doing a lot of active work on the board. The rooks tend not to get as involved in the early stage of the game as you want to have some open files for them to use rather than having them get pushed around the board by your opponent. So although you've made a fair trade points-wise, you're now missing two key pieces in a stage of the game where they really make a difference and you're gambling on scraping through the middle game without them for long enough to cash in on that extra rook advantage later in the game.

I think it is because once you have done that that leaves the opponent's king exposed for your queen or other rook/bishop/knight for pursuit or attack.

It always depends on the specific position, but generally this trade is better for the side who gives up the rook + pawn and gets the bishop + knight. If this is going to happen it's usually quite early in the game and the 2 minor pieces have much greater potential at this point than the rook + pawn. 

No, because 2 pieces are better than a rook, and the pawn doesn’t even balance it out. Sure, material is the same, but your opponent will have more pieces and thus could overpower you.

And also, you will not use rooks in the middle game that much. They might be on an open file but that is it usually, unless you are attacking. Still, having 2 minor pieces in an attack is better than a rook depending on the position.

Iń general, itś not ok. Sorry for the weird accents in my text btw, dónt even ask

I will! Why are there accents in your text?

No no...They would be UP a pawn.

Hi! My name is Lauren Goodkind and I’m a chess coach  based in California: www.ChessByLauren.com. 

 It depends on the position.  Usually, it's better to have the knight and bishop than trading it off for a rook and a pawn.  Why?  The knight and the bishop are more active than the rook and the pawn.  

    I hope that this helps.  

Generally it is a bad trade for the side who gives up 2 minor pieces, especially in the beginning of the game.

The thing is this. Rooks are generally not that active in the beginning of the game, and minor pieces are. So you would be trading already moved minor pieces for a rook that perhaps only moved as part of castling. Look at it this way: Not only you are trading 6 points of material for 6 points of material, but you are trading the time you already spent on moving those pieces for the time used on moving the rook and a pawn. In the case you describe, it is most likely that your opponent will have a lead in development, so that trade is generally not good for you.

Sometimes even a rook and 2 pawns are not good enough compensation for 2 minor pieces (especially 2 bishops), but this trade can be favorable as well, it is more uncertain. 

That's a really interesting thought,  I'd never really thought about valuing a piece as being the point value + the amount of work you'd put in to developing them.

I knew that it was often a good idea to trade one of your undeveloped pieces for an opponent's active piece so I'd often initiate an exchange on that basis but to think of it as a formula along the lines of (points+development=exchange value) actually works quite well for my way of thinking!

Well that is only one point of view you can consider. You can visualize the starting point of the transaction and the end point of the same transaction so to speak. You'll see that at the beginning white has 2 developed pieces, and after the trade, he has none. So if he didn't win some material, you might conclude that the trade is not good enough. 

That is one of the reasons you often try to make your opponent exchange rooks on the open file. You want your undeveloped rook to come to that file, not his. Every trade should be carefully considered. "Even" trade is often not so even.

its very unbalanced. In some positions in endgames, lone rook is superior to two minor pieces, if the coordination between pawns and the pieces is horrendous but two pieces are slightly to much better   usually(With two bishops being almost always being decisive, with two knights it depends heavily on pawn islands).

a pawn doesnt usually add much to the dynamic unless it is directly threatening promotion in some form with the rook. You sometimes even see a bishop and knight only be about equal to a rook and two pawns if its done in the middlegame.

Basically, it is position sentitive but these are a few hints

1. the closer to the endgame, the more likely the rook can hope to hold its own, but only if it has lots of movements and the opponent has pawn weaknesses or the minor pieces are prone to being harrassed. 

2. the two piece side, is hoping to gain further material advantage or create more threats in  the middlegame, and create stable targets he can attack twice in an endgame. The rook side, wants to get as many pawns alongside the rook. The extra pawn being further from the beginning position also helps, as bishop and knight can be sloppy in stopping a passer. extra points if pawns are side by side as the rook may only need  to babysit one of the pawns,although this isnt universal, sometimes having spaced out promotion threats can be better

The Bishop is the piece that cannot be replaced unlike the Rook and Knight. The exchange is equal and some people will go for it when pushed but the weakness left by the Bishop's exchange will soon show and quite a few pawn moves will be needed to shore up the position.

It usually results in a .losing position to trade your knight and  bishop for a rook and pawn.