Jawabanmu

2014-09-01T20:25:16+07:00
A. log18= (9.2) = log (3.3.2) = log 3 x log 3 x lg 3 = 0.4771 + 0,4771 + 0,3010 = 1,2552
b. log 21 = log (7.3) = log 7 + log 3 = 0,8451 + 0,4771 = 1,3222
 cuma bisa itu dan aku cuma dsurh ngerjain soal a,b doang. semoga membantu dan tolong dicek lagi:)
2014-09-01T20:26:24+07:00
A. log 18 = log 2.3.3= 0.3010 +0.4771+0.4771 = 
b. log 21= log 3.7 = 0.4771 + 0.8451 =
c.log 10,5 = log 3.7 dibagi 2 = 0.4771+0.8451-0.3010 =
d. log 1 per 7 = log 2 per log 7 =  0.4771-0.8451 =
itung sendiri hasilnya