化简求值:若4x²+4xy+2y²-6y+9=0试求(x²+2y²+3)(x²+2y²-3)-(x-2y)²(x+2y²)
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化简求值:若4x²+4xy+2y²-6y+9=0试求(x²+2y²+3)(x²+2y²-3)-(x-2y)²(x+2y²)
化简求值:若4x²+4xy+2y²-6y+9=0
试求(x²+2y²+3)(x²+2y²-3)-(x-2y)²(x+2y²)
化简求值:若4x²+4xy+2y²-6y+9=0试求(x²+2y²+3)(x²+2y²-3)-(x-2y)²(x+2y²)
4x²+4xy+2y²-6y+9=0
4(x+y)²+(y-3)²=0
由非负性知道
y-3=0
x+y=0
x=-3
y=3
(x²+2y²+3)(x²+2y²-3)-(x-2y)²(x+2y²)
=(9+18+3)(9+18-3)-(-9)²(3)²
=30×24-27²
=27²-3²-27²
=-9