1)8x^3+125=(2x)^3+5^3
a^3+b^3=(a+b)(a^2-ab+b^2)=(2x+5)(4x^2-10a+25)
2) x^2-x-y^2-y=(x-y)(x+y)- (x+y)=(x+y)(x-y)-1)
3) -4x^5*y^2*3xy^4=-12x^6*y^6
4)(3x^2y^3)^2=9x^4y^6
