Resposta :
A-B+C =
(2x+4y+5)-(2x+2y-3)+(4x-y+4)=
2x+4y+5-2x-2y+3+4x-y+4=
2x-2x+4x+4y-2y-y+5+3+4=
4x+y+12 #
(2x+4y+5)-(2x+2y-3)+(4x-y+4)=
2x+4y+5-2x-2y+3+4x-y+4=
2x-2x+4x+4y-2y-y+5+3+4=
4x+y+12 #