Hey guys, I can't seem to figure this problem out, can anyone help??

its:

y = 1 / ln (cx)

find derivate of y... and the value of c is found by rearranging the equation above and isolating c

I keep getting that c = 1 / xe^y

and then i get that the derivative is y' = e^y / (ln (1/e^y)^2 but i know its wrong because the answer should be: y' = -y^2 / x