Respuesta :
y^2 + 18y + 81 = 0
y^2 + 9y + 9y + 81 = 0
y(y + 9) + 9(y + 9) = 0
(y + 9) (y + 9) = 0
so
y + 9 = 0
y = -9
___________________________
the correct answer = C
y^2 + 9y + 9y + 81 = 0
y(y + 9) + 9(y + 9) = 0
(y + 9) (y + 9) = 0
so
y + 9 = 0
y = -9
___________________________
the correct answer = C