原式=5abc-{2a²b-[3abc-(4ab²-a²b)]}
=5abc-[2a²b-(3abc-4ab²+a²b)]
=5abc-(2a²b-3abc+4ab²-a²b)
=5abc-2a²b+3abc-4ab²+a²b
=(5abc+3abc)+(-2a²b+a²b)-4ab²
=8abc-a²b-4ab²
当a=2/3,b=3/2,c=1时
原式=8×2/3×3/2×1-(2/3)²×3/2-4×2/3×(3/2)²
=8×2/3×3/2×1-4/9×3/2-4×2/3×9/4
=8-2/3-6
=4/3