|a+1|+（b-2）²=0
a+1=0,a=-1
b-2=0,b=2
5ab²-｛2a²b-3【ab²-2（2ab²+a²b】）｝
=5ab²-[2a²b-3(ab²-4ab²-2a²b)]
=5ab²-(2a²b-3ab²+12ab²+6a²b)
=5ab²-8a²b-9ab²
=-4ab²-8a²b
=-4x(-1)x4-8x1x2
=16-16
=0
不懂的欢迎追问.