function y=fx(x)
y=x.^3+4*x.^2-10;
endfunction

% The part above is typed in a separate function file with the same name i.e. fx.m
% No need for the word 'endfunction' in the function file.
% The part below is performed at the command line separately

root=fzero(@fx,1.6)

or

root=fzero('fx',1.6)