71.1-65 = (74.8-65)2.718^(-2k)
6.1 = (9.8)(2.718^-2k)
6.1/9.8 = 2.718^-2k
0.62244 = 2.718^(-2k)
log 0.62244 = -2k log 2.718
-0.2059 = -2k (0.43424)
-0.2059/0.43424 = -2k
-0.474 = -2k

k = 0.237

74.8-65 = (96.6-65)2.718^(-0.237t)
9.8 = 31.6*2.718^(-0.237t)
9.8/31.6 = 2.718^(-0.237t)
0.3101 = 2.718^(-0.237t)
log 0.3101 = -0.237t log 2.718
-0.5084 = -0.237t (0.43424)
-0.5084/0.43424 = -0.237t
-1.17 = -0.237t
-1.17/0.237 = -t

t = -4.936 hours = 4 hours 54 minutes
first temp. measurement time: 6:05
6:05-4:54 = 1:11.

Time of death: 1:11 am.