先化简,再求值:-a^2b+(3ab^-a^2b)-2(2ab^2-a^2b),其中|a-1|+(b+2)^2=0.

|a-1|+(b+2)^2=0.
a-1=0 b+2=0
a=1 b=-2
-a^2b+(3ab^-a^2b)-2(2ab^2-a^2b)
=-a^2b+3ab^-a^2b-4ab^2+2a^2b
=-ab^2
=-1*(-2)^2
=-4