I'll give brainliest if I get the question correct. =)

Step-by-step explanation:
We have logb(8) = 3 and logb(0.5) = -1.
=> b³ = 8 and 1/b = 0.5
=> b = 2.
Therefore,
logb(4b) = log2(8) = 3.
Answer:
We have, logb(8)=3 and logb(0.5)=-1
→b³=8 and 1/b=0.5
→b=2
Therefore,
logb(4b) = log2(8)=3.