funk = '3*x^2-6*x+1';
f = inline(funk);
a = -10;
b = 10;
minv = f(a);
minx = a;
fb = f(b);
if fb < minv
    minv = fb;
    minx = b;
end
d = diff(sym(funk));
mzerowe = solve(d);
for i=1:length(mzerowe)
    if f(mzerowe) < minv
        minv = f(mzerowe);
        minx = mzerowe;
    end
end

minv
minx