(-a-4b-ab)-(2ab-2a-3b)-(3ab+2b-2a)
=-a-4b-ab-2ab+2a+3b-3ab-2b+2a
=(-a+2a+2a)+(-4b+3b-2b)+(-ab-2ab-3ab)
=3a-3b-6ab
=3(a-b)-6ab
=3x3-6x(-3)
=9+18
=27
(-a-4b-ab)-(2ab-2a-3b)-(3ab+2b-2a)
=-a-4b-ab-2ab+2a+3b-3ab-2b+2a
=3a-3b-6ab
=3(a-b)-6ab
=3x3-6x(-3)
=9+18
=27