(a^3-6a)^2
(a-x)^2(x+a)^2

100a^4-1/9b^2
9x^2-(x-1)^2
x^3+y^6

=a⁶-12a⁴+36a²=((a-x)(a+x))²=a⁴-x⁴=(10a²-1/3b)(10a²+1/3b)=(3x-x+1)(3x+x-1)=(2x+1)(4x-1)=(x+y²)(x²-xy²+y⁴)