Answer: Hello there!
Let's use some relations:
log(a*b) = log(a) + log(b)
log(a/b) = log(a) - log(b)
log(1) = 0
log(a^b) = b*log(a)
now, we know that log(7) = 0.8451.
we want to finde log(1/7000)
log(1/7000) = log(1) - log(7000) = 0 - log(7000)
=- log(7*1000)
we can write 1000 as 10^3
=- (log(7) + log(10^3)) = -(0.8451 + 3*log(10))
and log(10) = 1
then we have:
-(0.8451 + 3*log(10)) = -(0.8451 + 3*1) = -3.8451