factorization~~~~~~~

1.
x^3 y^3-(x+y)^3
= (x+y)(x^2-xy+y^2) - (x+y)^3
= (x+y)[x^2-xy+y^2-(x+y)^2]
= (x+y)(x^2-xy+y^2-x^2-2xy-y^2)
= (x+y)(-3xy)
= -3xy(x+y)

OR:
= x^3+y^3-x^3-3x^2 y-3xy^2-y^3
= -3x^2 y-3xy^2
= -3xy(x+y)


2.
x^6-64
= (x^3)^2-8^2
= (x^3+8)(x^3-8)
= (x+2)(x^2-2x+4)(x-2)(x^2+2x+4)

3.
4a^2(y-2)^2-a^2
= a^2[4(y-2)^2-1]
= a^2[4(y-2)+1][4(y-2)-1]
= a^2(4y-8+1)(4y-8-1)
= a^2(4y-7)(4y-9)

1) x+y-(x+y)
=(x+y)(x-xy+y)-(x+y)
=(x+y)[(x-xy+y)-(x+2xy+y)]
=(x+y)(-3xy)
=-3xy(x+y)
2)x6-64
=x6-26
=(x2)3-(22)3
=(x2-22)(x4+4x2+16)
=(x-2)(x+2)(x4+4x2+16)
３）　4a2(y-2)2-a2
=a2[4(y-2)^2-1]
=a2[(y-2)-1][(y-2)+1]
=a2(y-3)(y-1)