log is a function and therefore we need an argument to talk about it's value.
Explanation:
log(x) is whatever value y which is required to make 10^y = x
log(1000) is 3 since 10^3=1000
The default base for log as seen above is 10.
Other bases can be specified as: color(white)("XXX")log_3(x) which would be the value y needed to make 3^y =x color(white)("XXX")log_3(81) = 4 since 3^4=81