The given function is
f(x) = log₁₀(5x-1)
As x -> -∞, the argument of the log function becomes a large negative number.
Because the log of a negative number is undefined, f(x) is undefined as x -> -∞.
As x -> +∞, the argument of the log function becomes a large positive number.
Therefore f(x) -> +∞ as x -> +∞.
Answer:
As x -> -∞, f(x) is undefined.
As x-> +∞, f(x) -> +∞.