Question

can someone check my answers ?

Factor Completely: 40xy^2 − 36x^2y.
4xy(9y − 10x)
4xy(10y − 9x)<--- answer
Prime
4xy(10x − 9y)

What are the factors of x2 − 81?
(x + 9)(x − 9)<--- answer
(x − 9)(x − 9)
(x + 3)(x − 27)
Prime

Which polynomial is a difference of two squares?
x2 − 16
x2 + 16
x2 − 8
x2 + 8<--- answer

Factor completely: 12x3y + 6x2y2 − 9xy3
3x2y(4x2 + 2xy − 3)
3xy(4x + 2xy − 3y2)
3xy(4x2 + 2xy − 3y2)<----- answer
3x2y(4x3y − 2x2y2 − 3xy3)