Factorize of polynomials(F3)

1).(x+y)^4-(x-y)^4

= ((x+y)^2)^2 - ((x-y)^2)^2

= [ (x+y)^2 - (x-y)^2 ][ (x+y)^2 + (x-y)^2 ]

= [(x^2 + 2xy + y^2) - (x^2 - 2xy + y^2)][(x^2 + 2xy + y^2 + x^2 - 2xy + y^2)]

= 4xy(2x^2 + 2y^2)

= 8xy(x^2 + y^2)

2)9w^2-24wz+16z^2-36x^2-36xy-9y^2

= (9w^2-24wz+16z^2) - (36x^2 + 36xy + 9y^2 )

= [(3w)^2 - 2(3w)(4z) + (4z)^2] - [ (6x)^2 + 2(6x)(3y) + (3y)^2]

= (3w - 4z)^2 - (6x + 3y)^2

= [(3w - 4z) + (6x + 3y)][(3w - 4z) - (6x + 3y)]

= (3w+6x+3y-4z)(3w-6x-3y-4z)