Mark M. answered 06/22/21
Retired math prof. Calc 1, 2 and AP Calculus tutoring experience.
The given limit has the indeterminate form 0/0. So, L'Hopital's Rule is applicable.
Applying the rule, the given limit is equivalent to:
limx→0 [ (4x + xln4(4x)) / (ln4(4x)) ] = limx→0 [(1 + xln4) / (ln4) ] = 1 / ln4