I don't understand the explanation. Doesn't the assembler have to calculate 3 * 4 + 5 so it takes longer to execute? Also since 3 * 4 +5 has more characters why does it not take more storage?
The assembler (compiler) has to calculate the constant at assembly time, so the compilation to binary is marginally slower. A human cannot tell the difference so the compilation time it takes is irrelevant.
The resulting assembly binary will be identical, so they are both equally sized and equally fast programs.