1.(-a^2)^3*(-a^3)^2=(-a^6)(a^6)=-a^12
2.(-1/4)^5*(1/4)^3*(-1/4)^2=(-1/4^5)(1/4^3)(1/4^2)=-(1/4)^(5+3+2)=-(1/4)^10
3.-(m^a*n^b)^2*(m^2*n)^3=-(m^2a*n^2b)*(m^6n^3)=-m^(2a+6)*n^(2b+3)
4.(-2a^2*b)^3+8(a^2)^2*(-a)^2*(-b)^3
=(-8a^6*b^3)-8a^4*a^2*b^3
=-8a^6*b^3-8a^6*b^3
=0
5.(-3a^2)^3*a^3+(-4a)^2*a^7-(5a^3)^3
=(-27a^6)*a^3+(16a^2)*a^7-125a^9
=-27a^9+16a^9-125a^9
=(-27+16-125)a^9
=-136a^9