Resposta :
(x+3y)²+6x-1y=4x(-1y+3)
x^2 + 6xy +9y^2 + 6x -1y = -4xy + 12x
x^2 + 9y^2 + 6x - 12x + 6xy + 4xy - 1 y = 0
x^2 + 9y^2 - 6x + 10xy - 1 y = 0
x^2 + 6xy +9y^2 + 6x -1y = -4xy + 12x
x^2 + 9y^2 + 6x - 12x + 6xy + 4xy - 1 y = 0
x^2 + 9y^2 - 6x + 10xy - 1 y = 0