Factor out a variable from a function

[phil1958]

I have a funcion f(x1,x2,x3)
Is there any procedure in (Wx)Maxima to factor out x1, x2 and x3 to get g(x1,x2,x3) = x1f1(x2,x3) + x2f(x1,x3)+ x3*f3(x2,x3) ?

[phil1958]

... or factor f(x1,x2,x3) like this: f(x1,x2,x3) = f1(x1) + f2(x2) + f3(x3) ?