Jawabanmu

2014-07-24T12:12:35+07:00
a.  ²log 1/8 = x
     1/8 = 2^x
      8^-1 = 2^x
      2^(3 x (-1)) = 2^x
      x = -3        
b. 2/5 log 4/25 = x
    (
2/5)^x = 4/25
     (2/5)^x = (2/5)^2
      x = 2
c. ²log (√72+√8) = x
    2^x = 
(√72+C)
    2^x = 3√8+√8
    2^x = 4√8
    2^x = 2^2 . 2^(3/2)
    2^x = 2^(2 + 3/2)
      x = 2 + 3/2 = 7/2