Solving equation equal to zero with multivariables

m=[ 4000 50 ] ; 
ls=[];

n=length(m) ;
for i = 1 : n
    eval(sprintf('syms x%i,',i));
    eval(sprintf('x(%i) = x%i;', i, i));
end
Y= @(x1, x2) 29-(6*x(1))-(18*x(2));

  for i=1:n
  temp =(-diff(Y,x(i)));   
  ls=[ls, temp];
  end
  
  for i=1:n  
    if i<n
        x(i)=m(i);
    disp(x);
    disp(i);
    else
        x(i)=fsolve(Y,double(x));
        disp("aa");
        %=>>>>>>>>>>>>>> 5
    end   
  end   

  disp(ls) ;
  last=lenght(ls) 
  first = ls(last)
  
  

when i was trying to run this code i got this error:

  Error using symengine
Unable to convert expression into double array.
Error in sym/double (line 692)
        Xstr = mupadmex('symobj::double', S.s, 0);

i am trying to find a value of x2 with the use of the function y equal to zero and with using x1 equal to 4000

Answer 1

[sarra aloui]

thank you for your help but how can i make it for n number of x that i have (n-1) values of m and i am looking for the last value from the equation Y equal to zero