log327 + log364 

log 27 base 3

That means the exponent (power) to which you must raise 3 to get 27.
Since we must raise 3 to the 3rd power to get 27, then: 

log 27 base 3 which is written log327 = 3 because 33 = 27.  

So

log 64 base 4

That means the exponent (power) to which you must raise 4 to get 64.
Since we must raise 4 to the 3rd power to get 64, then:  

log 64 base 3 which is written log364 = 3 because 43 = 64.

So answer = log327 + log364 = 3+3 = 6.

Edwin