How do you solve logarithmic equations like this one?

How do you solve

$3\mathrm{log}(x-15)={\left(\frac{1}{4}\right)}^{x}?$

The solution is approximately 16. How would you solve a logarithmic equation with an solution approximately equal to a number without using a graphing calculator?

How do you solve

$3\mathrm{log}(x-15)={\left(\frac{1}{4}\right)}^{x}?$

The solution is approximately 16. How would you solve a logarithmic equation with an solution approximately equal to a number without using a graphing calculator?