We express the expression as 2 being the base of the terms above.hence this can be expressed as ln (1-3x) / ln 2 .Since 1/ ln 2 is a constant, we can just carry out this constant beside the derivative of ln (1-3x). the derivative of ln (1-3x) is -3/(1-3x). Hence the answer is -3/ln 2* (1-3x)
