Resposta:
(2x + 5xy - y³) + (7x - 2xy + 6y²)
[tex](2x+7x)+(5xy-2xy)-y^{3} +6y^{2} =\\ \\ 9x+3xy-y^{2}(y+6) =\\ \\ 3x(3+y)-y^{2}(y+6)[/tex]
