3 = log(8) + log(x³)
When adding logs, you are multiplying the terms altogether.
3 = log(8x³)
Then, by log_a b = n ==> aⁿ = b:
10³ = 8x³ [Since the base is not given, I assume that the base is 10]
1000 = 8x³
Finally, solve for x.
1000/8 = x³
x³ = 125
x = (125)^(1/3) . . .Set both sides to the power of 1/3.
x = 5
Hence, x = 5.