Q:

How do I use "Factor" to get this form

Here is the default answer.

However, I want to get the result which looks like this

Here is the Mathematica code:
Factor[Subscript[x, 1] Subscript[x, 2] + Subscript[x, 1] Subscript[x, 3] Subscript[x, 4] + Subscript[x, 1] Subscript[x, 3] Subscript[x, 5]]

Is it possible on Mathematica?

A:

HornerForm[x1 x2 + x1 x3 x4 + x1 x3 x5]
(* x1 (x2 + x3 (x4 + x5)) *)

