a-1的绝对值+b-2的绝对值+c^2=0
∴ a-1=0
b-2=0
c=0
∴a=1,b=2,c=0
5abc-2a^2b+[3abc-2（4ab^2-a^2b)].
=5abc-2a²b+3abc-8ab²+2a²b
=8abc-8ab²
=0-8×1×4
=-32