Maths, equations exponencials to potencials

I am sorry I don't understand your question.

how trasform I(z)=I(0)*e^ln(1/10)*z in a potencial equation??

x(z)?
I(0)?

e ^ln(1/10) = 1/10
e and log _e cancel each other out but that is all I can help with. I don't understand the rest of your question.

okey in the maths question I have:

I(z) = I(0) * e^(-a*z)

I found, a that in the first paragraph says that at Z = 1 the equation is 10%, but later said me that I have to transform this exponential equation to a potential equation.

Okay, I still don't understand, maybe you are studying maths that I have not done or maybe the meaning just gets lost in the translation.
I have not heard the term potencial equation before, do you just mean an equation that is not exponential? (no powers)

Your original question was
how trasform I(z)=I(0)*e^ln(1/10)*z in a potencial equation?
I am going to assume l is a function.

I(z)=I(0) * e ^ln(1/10) * z

I(z)=I(0) * (1/10) * z

I(z)=I(0) * z * (1/10)

I(z)=I(0) * z / 10
-------------------------------

l(0) = l(0) * 0/10 = 0
so
I(z)=I(0) * z / 10 = 0*z/10 = 0

So, with my limited understanding of your problem I get an answer of 0

Just in case you have already seen my answer, I did fix a little typo in the first line of the solution.