[tex]4a^2(b^2-c)+2ab(ab-c)-ac(a+2b)\\-----------------------\\use\ distributive\ property:a(b-c)=ab+ac\\-----------------------\\=4a^2b^2-4a^2c+2a^2b^2-2abc-a^2c-2abc\\=(4a^2b^2+2a^2b^2)+(-4a^2c-a^2c)+(-2abc-2abc)\\\\=\boxed{6a^2b^2-5a^2c-4abc}[/tex]