Exponential functions are inverses of logarithmic functions.
by = x if and only if y = logb x for all x > 0 and 0 < b ≠ 1.
Remember a logarithm is an exponent!
Example 1:
Write 23 = 8 in logarithmic form.
log2 8 = 3
Example 2:
Write ca = d in logarithmic form.
logc d = a