125a^3-64x^3=(5а-4х)(25а²+20ах+16х²)

x^3+x^2y-4y-4x=(х+у)(х-2)(х+2)

Verified answer

[tex]\displaystyle 1)125a^3-64x^3=5^3a^3-4^3x^3=(5a)^3-(4x)^3=(5a-4x)((5a)^2+5a*4x+(4x)^2)=(5a-4x)(25a^2+20ax+16x^2)\\\\2)x^3+x^2y-4y-4x=x^2(x+y)-4(y+x)=(x+y)(x^2-4)=(x+y)(x-2)(x+2)[/tex]