Respuesta :

| - 4 | = 4

Thus :

f ( | - 4 | ) = f ( 4 )

f ( 4 ) = ( 4 )^2 - 2(4) + 4

f ( 4 ) = 16 - 8 + 4

f ( 4 ) = 16 + 4 - 8

f ( 4 ) = 20 - 8

f ( 4 ) = 12