x^25÷[(-x^2)^3]^4·(-x^3)^2÷(-x^2)^5
=x^25÷x^24·x^6÷(-x^10)
=x·x^6÷(-x^10)
=x^7÷(-x^10)
=-1/x^3
(a-b)^5·(b-a)^2÷(b-a)^3
=[-(b-a)]^5·(b-a)^2÷(b-a)^3
=-(b-a)^5·(b-a)^2÷(b-a)^3
=-(b-a)^(5+2-3)
=-(b-a)^4
2.2×10^10/1.1×10^12=2*10^-2=0.02
a^3(-b^3)^2+(-1/2ab^2)^3
=a^3*b^6+(-1/8ab^6)
=(ab)^3*b^3+(-1/8ab^6)
a=0.25 b=4 ab=1
原式=1^3*4^3+(-1/8*1^6)
=1*64-1/8
=511/8