-1/2a^2b+2a^3+4a^2b-5a^2b-5a^3,其中a=-1,b=-1/3

-1/2a^2b+2a^3+4a^2b-5a^2b-5a^3,其中a=-1,b=-1/3
-1/2a^2b+2a^3+4a^2b-5a^2b-5a^3,其中a=-1,b=-1/3

-1/2a^2b+2a^3+4a^2b-5a^2b-5a^3,其中a=-1,b=-1/3
原式=-1/2a²b+2a³+4a²b-5a²b-5a³
=(-1/2a²b+4a²b-5a²b)+(2a³-5a³)
=-3/2a²b-3a³
当a=-1,b=-1/3时
原式=-3/2×(-1)²×(-1/3)-3×(-1)³
=-3/2×1×(-1/3)-3×(-1)
=1/2+3
=7/2