(x - 6*y)*(x + 6*y)
(x - 6*y)*(x + 6*y)
1*(x + 6*y)*(x - 6*y)
(1*(x + 6*y))*(x - 6*y)
(x - 6*y)*(x + 6*y)
(x - 6*y)*(x + 6*y)
2 2 x - 36*y
(x - 6*y)*(x + 6*y)
(x - 6*y)*(x + 6*y)
(x - 6*y)*(x + 6*y)
(x - 6*y)*(x + 6*y)
(x - 6*y)*(x + 6*y)
(x - 6*y)*(x + 6*y)