2(a^2b+2b^3-ab^2)+3a^2-(2ba^2-3ab^2+3a^2)-4b^3
=2a^2b+4b^3-6b^2+3a^2-2a^2b+3ab^2-3a^2-4b^3
=3ab^2-6b^2
=3*(-3)*4^2-6*4^2
=-144-96
=240
2(a^2b+2b^3-ab^2)+3a^2-(2ba^2-3ab^2+3a^2)-4b^3
=2a^2b+4b^3-6b^2+3a^2-2a^2b+3ab^2-3a^2-4b^3
=3ab^2-6b^2
=3*(-3)*4^2-6*4^2
=-144-96
=240