9a^2-[-6a^2+2(-a^3-2/3a^2)]先化简,再求知.A=12

9a^2-[-6a^2+2(-a^3-2/3a^2)]先化简,再求知.A=12
9a^2-[-6a^2+2(-a^3-2/3a^2)]
先化简,再求知.A=12

9a^2-[-6a^2+2(-a^3-2/3a^2)]先化简,再求知.A=12
9a²-[-6a²+2(-a³-2/3a²)]
=9a²-(-6a²-2a³-4/3a²)
=9a²+6a²+2a³+4/3a²
=49/3a²+2a³
=49/3a²(1+2a)
=49/3×12²×(1+2×12)
=58800