A^3 - 125 = (a - 5)(a^2 + 5a + 25)
64 + x^3 = ( 4 + x)(16 - 4x + x^2)
a^2 - 81 = ( a - 9)(a + 9)
n^3 - 25n= n(n^2 - 25) = n( n - 5)(n + 5)
(3x + y)(x + y) - 4y( x - y) = 3x^2 + 3xy + xy + y^2 = 3x^2 + 4xy + y^2
( y - 10)(y - 2) + (y + 4)(y - 5) = y^2 - 12y + 20 + y^2 - y - 20 = 2y^2 - 13y