a) (x^2-2x^2)(-3x^5)= -x^2(-3x^5)=3x^7
b) [8a^14:-4a^4)-3a^5]:a^5= (-2a^10 - 3a^5):a^5 = -a^5(2a^5-3):a^5=-(2a^5-3)=-2a^5+3
c) m^2 * 4m^2- 4m^2+m^4-81m^4 =
4m^4-4m^2-80m^4=-76m^4-4m^2 daca in loc de -2(2m^2) era -2(2m^2)^2, rezultatul era -80m^4
d) 256x^8: (4x^4)^2 = 256x^8: 16x^8 = 16
e) (0,4p - 0,8p^4 : 0,4p^3 -1/5p)^2
=(0,4p - 2p - 1/5p)^2 = (-1,8p)^2=3,24p^2