Jawabanmu

2014-08-19T18:58:59+07:00
Log 81 = log 3^4 = 0.4771 + 0.4771 +0.4771+0.4771 = 1.9084
log 21 = log 3 x log 7 = 0.4771 + 0.8451 = 1.3222