Factor Command
From GeoGebra Manual
This command differs among variants of English:

 Factor[ <Polynomial> ]
 Factors the polynomial.
 Example:
Factor[x^2 + x  6]
yields (x  2) (x + 3).
Note: This command needs to load the Computer Algebra System, so can be slow on some computers.
Hint: In the CAS View you can also use the following syntax:
 Factor[ <Number> ]
 Expresses a number in its prime factorization
 Example:
Factor[360]
yields 2³ 3² 5.
 Factor[ <Expression>, <Variable> ]
 Factors an expression with respect to a given variable.
 Example:

Factor[x^2  y^2, x]
yields (x  y) (x + y), the factorization of x^{2}  y^{2} with respect to x, 
Factor[x^2  y^2, y]
yields (y  x) (y + x), the factorization of x^{2}  y^{2} with respect to y.

Note: This command factors expressions over the Rational Numbers. To factor over irrational real numbers, see the IFactor Command. To factor over complex numbers, see the CFactor Command and CIFactor Command.