format short
syms x y z
f=6*(x^2+2*x)+5*(y^2+4*y)+4*(z^2-6*z)+100;
t=0.1;
a=1;
b=1;
c=1;
k=0;
while k<10
    dFx=diff(f,x);
    dFy=diff(f,y);
    dFz=diff(f,z);
    dFx=subs(dFx,{x,y,z},{a,b,c});
    dFy=subs(dFy,{x,y,z},{a,b,c});
    dFz=subs(dFz,{x,y,z},{a,b,c});
    X0=[a b c];
    X1=X0-t*[dFx dFy dFz];
    a=X1(1);
    b=X1(2);
    c=X1(3);
    k=k+1;
    M=double(X1)
end