How are eth transaction faster than btc? If I'm not wrong miners are trying to find nonce that satisfies a rule.

Then why is btc so slow? I want a technical answer.

Can btc ever match eth speed, given no politics?
Most simple and foreseen reason:

Bitcoin's blocktime is set at 10 minutes, 
while Ethereum has a block every 10-20 seconds, making it much faster.


  See Ghost protocol, https://www.cryptocompare.com/coins/guides/what-is-the-ghost-protocol-for-ethereum/


So no, bitcoin will probably never be able to match Ethereum's speed. ( In it's current state)

(Unless they would implement something like the lightning network.)