Bitcoin mining has been always profitable and will be always profitable.
Will you mine bitcoin if it costs you more than the price you can buy it in the market?
If the money someone has to spend for mining 1 bitcoin is higher than bitcoin price, the person will no longer mine bitcoin. This causes the total hashrate of the network to decrease. With the decrease in the total hash rate, the difficulty and the mining cost will decrease too. So, mining is always profitable.

Even if bitcoin reaches 1 million dollars and the mining cost increases significantly, people can still join mining pools and continue to mine bitcoin. You don't have to mine a block alone. Note that even now almost no one is able to do so and people join mining pools.

You are saying that you imported a private key and you didn't get the address you expected. You also imported the same private key into electrum and got a correct address but the wallet was watch-only.
And now you are asking why the electrum watch-only wallet generated the correct address while other wallets generated a wrong address.
Am I getting you right?

If so, as mentioned by pooya87, you have imported a wrong private key.
And you see a correct address on the electrum watch-only wallet, because you imported the address not the private key.

Don't say you imported a private key into electrum and it created a watch-only wallet. That's impossible.

This can't be the problem.
I just visited ChangeNOW and selected a disabled pair.
They didn't give me a deposit address at all. I got an error saying "Trading pair is not available now. Please, check back later."
As others said, the problem is probably that they don't track the new transaction when the original one is replaced by another one using RBF feature.

Correct.
There is no transaction on the blockchain to be shown.
Coinbase displays a number as your balance and promise that you can withdraw that. This promise can be broken at any time.


Correct.
As long as your fund is on coinbase, they have full control over that.
If they disappear for any reason, you will lose your money.


It's recommended to move your bitcoin to your own wallet. In this way, you can have full control over your fund.
If your wallet is a cold wallet, you can be more secure.


Your wallet should show a same transaction.

You haven't withdrawn the fund yet. Have you?
If you just bought bitcoin and you haven't withdrawn that, no transaction has been made and there is no transaction ID.
Note that the fund is still on coinbase wallet and you can request a withdrawal. If you do so, then coinbase will make a transaction and will give you the transaction ID.

If you have access to the email address used for creating your wallet, search for blockchain in your email inbox. Your wallet ID can be found at bottom of any email they have sent to you.
Just note that even if you can find the wallet ID, you need the password too. Without that you can't access your wallet.

I start the answer to your question with bitcoin.
Once a transaction is confirmed (I mean it gets 1 confirmation), it's almost secure and it's very unlikely that someone can change it. But that's not 100% secure.
It's possible that your transaction never receive next confirmations. Because, there is no guarantee that next block will be added to the chain including your transaction. Your transaction is also vulnerable to a 51% attack.
More confirmations your transaction receives, more secure it becomes.

Every coin has a different total hash power and the cost to implement a 51% attack is different for each of them. That's why exchanges wait for different number of confirmations.
Also, some coins like BNB use the POS system and that's probably why FTX is accepting BNB transactions with a single confirmation.
Note that there is no exact number as number of required confirmations and that depends on risk acceptance of the exchange.

No, it doesn't depend on where you have sent the coins from. Usually, there is no way to know where the fund has been sent from at all.

You probably mean deposit. Yes.
As said, the cost for implementing a 51% attack for different coins are different.
For example, a bitcoin transaction with 1 confirmation is much more secure than a bitcoin cash transaction with 10 (or maybe even more) confirmations.

Again, deposit not withdraw.
The cost of implementing a 51% attack may change over the time. But that's not significant and exchanges usually consider a fixed number of confirmations.  
So, the answer is NO.

As said, it depends on risk acceptance of the recipient. Number of required confirmations may vary in different exchanges.
Note that if you send bitcoin to me and I trust you enough, I can even accept an unconfirmed transaction.

This can happen only if you deal with a BIP39 seed phrase.
If the wallet has been originally generated by electrum, it's not possible to generate addresses with a different script type at all. Once you enter a seed phrase that has been generated by electrum, it automatically displays the seed type and you can't change that.

The post in question has been edited. (Note that you don't see the "last edit ..." message, because it has been edited in less than 10 minutes after its creation.)
As ninjastic.space searches in unedited versions of the posts and you are searching for the edited content, it can't find the post you are looking for.

To add to Charles-Tim's post:

In a M of N multi-signature wallet, M-N master public keys are also needed.
Let's say a wallet is 2 of 3. For making a transaction from this wallet, in addition to two master private keys, the public key of the third co-signer is also needed. Without that, it's not possible to setup the wallet.

It depends on how you implement it and how you make transactions.
If the two master private keys (or the corresponding seed phrases) always stay at separate devices, it can increase your security.

Let's say you have a 2 of 2 multi-signature wallet. The master private key A is kept on device A and the master private key B is kept on device B.
If you enter the master private key A on device B when making a transaction, it would defeat the purpose of the wallet. The two co-singers should sign the transaction in separate devices.

Also note that if you lose one of the master private keys, you will lose the access to the fund. So, I recommend you to consider a 2 of 3 multi-signature wallet too. In this way, you can keep three master private keys in three different places and you will still have access to the fund if you lose one of them for any reason.

In the case the wallet generated by electrum has been already funded, you can import it into bluewallet using its seed phrase.
It should be mentioned that, if there is no transaction in the wallet generated by electrum, it can't be imported into bluewallet.

No, that's impossible.

The only thing I can recommend you is to try to find the seed phrase. You may have saved or written that somewhere.
Also note that you have definitely enabled 2FA when creating the wallet. You may be able to find it on an old mobile phone.

Otherwise, there's nothing you can do and the fund is lost forever.

So, that's an outgoing transaction from your wallet. I thought you have received that.

You sent bitcoin from 1LNq5K... to 3CCj2oCUB.... and the change was sent to bc1qt35g6.....

I haven't ever used Bread wallet. It seems that breadwallet has sent the change to a segwit address while the wallet was legacy. If that's the case, a part of your balance is now in a legacy wallet and another part is in a segwit address.

What script type you selected when importing the seed phrase into electrum?
Select "native segwit (p2wpkh) and check if you see that 0.0747595 BTC.

Edit:
If it didn't work, click here and follow the guide posted by HCP.
It seems that Breadwallet use the derivation path of m/0'/1 for change addresses.

By the way, why don't you create a new electrum wallet and make a transaction from breadwallet to electrum?

To answer to this question, there is no need to mathematical calculations at all. The answer is the same for any public key.
Any public key can be generated by 2^96 private keys on average. Therefore, any known public key can be generated by numerous odd private keys and numerous even private keys.  

Sorry, there is exactly 1 private key for any public key.

That's not three transactions. That's a single transaction with 1 input and 2 outputs.
Assuming 3CCj2oCUB..... belongs to the wallet you imported into electrum, you should see the receiving amount of 0.025 BTC in your transaction history.
What's the problem now? Is electrum showing a different amount?

No, none of the three master public keys you have can help you to make a transaction.
As said, your wallet is actually a 2 of 3 multi-signature wallet. This means that for making any transaction two private keys are needed.

Your wallet includes only 1 master private key and since you don't have the seed phrase, any transaction you want to make has to be signed by trustedcoin.
Just wait for trustedcoin's response. There's nothing else you can do, unless you manage to find the seed phrase or the 2FA authenticator.  

Contact userhelp@trustedcoin.com.

In their "contact us" page, they say that they will ignore such requests.
But as already said, if you have neither the seed phrase nor the 2FA key, that's the only thing you can do. Try your luck. They  have been helpful in some cases.

By the way, are you sure that you haven't saved your seed phrase or written that somewhere? Are you sure that you don't have trustedcoin 2FA authenticator on an old phone?

Your wallet is actually a 2 of 3 multi-signature wallet. For making any transaction, 2 private keys are needed. Your wallet file includes only 1 private key.
If you have neither the seed phrase nor the 2FA code, the only thing you can do to is to contact trustedcoin and ask them to recover the 2FA.
Contact them with the email address you used when creating the wallet.

They may recover the 2FA, but they won't give the private key.