Question

先化简,再求值:[5a^4*a^2-(3a^6)^2/(a^2)^3]/(-2a^2)^2,其中a=-5

Answer 1

[5a^4*a^2-(3a^6)^2/(a^2)^3]/(-2a^2)^2

=(5a^6-9a^12/a^6)/(4a^4)

=(5a^6-9a^6)/(4a^4)

=-4a^6/(4a^4)

=-a^2