How to hash two bytes32 vars via keccak256 in the most gas-efficient way using Solidity keys

Question

I know how to get hash by using keccak256() function and here is the sample answer. bytes32 c = keccak256(abi.encodePacked(a, b)); But is this the only way and best way???

Answer 1

But is this the only way and best way???

Yes, unless you want to cause some pain for yourself.