Starting with ∫ax dx ,
We can re-write ax using logs as eln(a)*x using some of their properties
We use the substitution u = ln(a)*x (as such du/dx = ln(a)) allowing us to easily integrate eu with respect to u, by substituting du/ln(a) in the place of dx
The result is eu/ln(a) + c and after re-writing in terms of x by we get an answer of:
ax/ln(a) +c