5a^2b-[2a^2b-3(2abc-ac62)-5ac^2]-4abc
=5a^2b-2a^2b+6abc-3ac^2-5ac^2
=3a^2b+6abc-8ac^2
=3*9*4+6*-3*4*-1+8*3*1
=108+72+24
=224