problem with solving Equation

Hi, how can I solve this Equation '', when variable 'I' is used in loop previous lines. that means, I didn't take number 'I',but I have to use it in loop,How can I solve this problem?

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 % if true
    % code
clc

clear all

syms I

data=xlsread('Data','database');

capacity=data(:,1);

Uf=data(:,2);

co_m=data(:,3);

CA=data(:,4);

Kdg=0.9;

Ro=0.1*CA;

Co=0;

Cf=49;

Cs=0;

n=5;

sum=0;

P=200000000;

for j=1:length(data)

   Rm(j)=27.11*capacity(j)*Uf(j)*8760*Kdg;

   Co_m(j)=capacity(j)*co_m(j)*8760*Kdg ;

     Cfuel(j)=capacity(j)*Uf(j)*Cf*8760*Kdg;
ben(j)=Rm(j)-(Co_m(j)+Cfuel(j)+Cs);

end

for j=1:length(data)

    sum=0;

for i=1:5

 sum=((ben(j))/(1+I)^i)+sum==0;

end

sum

end

solve(-P+sum+(Ro-Co)*(1/(1+I)^n)==0,I)