FactorTerms

FactorTerms[poly] pulls out any overall numerical factor in poly.

FactorTerms[poly, x] pulls out any overall factor that does not depend on x.

Examples

Pull out numerical factor:

FactorTerms[2x + 4y]
(* 2 (x + 2 y) *)

Factor out terms not depending on x:

FactorTerms[a x + a y, x]
(* a (x + y) *)

Please visit the official Wolfram Language Reference for more details.