5ab²-｛2a²b-3【ab²-2（2ab²+a²b】）｝,其中a,b满足|a+1|+（b-2）²=0

5ab²－｛2a²b－【3ab²－（4ab²－2a²b】｝
=5ab¬¬2-{2¬¬¬a2b-[3 ab¬¬2-4 ab²+2a²b]}
=5ab¬¬2-2¬¬¬a2b+(3 ab¬¬2-4 ab²+2a²b)
=5ab¬¬2-2¬¬¬a2b+2¬¬¬a2b- ab¬¬2
=7ab¬¬2-3 a2b
(x²－4y²－2z²)-(－4x²+2y²+3z²)*2
=9x²-8y²-8z²
原式=7-(x-y)-(x-y)²
=7-3-3²=-5

1题
5ab²－｛2a²b－[3ab²－（4ab²－2a²b]｝
=5ab²-2a²b+[(3ab²－（4ab²－2a²b)]
=5ab²-2a²b+3ab²－（4ab²－2a²b)
=5ab²-2a²b+3ab²－4ab²+2a²b
=4ab²
2题：7-x+y-（y-x）²=7-（x-y)-（y-x)²=7-3-(-3)²=7-3-9=-5
3题：
x²－4y²－2z²-2（-4x²+2y²+3z²）=9x²-8y²-8z²

|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.

很简单,平方和绝对值互为相反数,那么只有等于0
2a+1=0得a=-1/2
6-3b=0得b=2,
原式=5ab*b-2a*ab+[3ab*b-4ab*b+2a*ab]
=5ab*b-2a*ab+3ab*b-4ab*b+2a*ab
=4ab*b
=4*（-1/2）*2*2
=-8