(2a-1)^2+|b+1|=0
2a-1=0,b+1=0
a=1/2,b=-1
2(3a^2-ab^2)-(2ab+2a^2)
=6a^2-2ab^2-2ab-2a^2
=4a^2-2ab^2-2ab
=4×1/4-2×1/2×1+2×1/2×1
=1-1+1
=1