若x+y=3,求½x²+xy+½y²的值.
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若x+y=3,求½x²+xy+½y²的值.
![若x+y=3,求½x²+xy+½y²的值.](/uploads/image/z/19324999-55-9.jpg?t=%E8%8B%A5x%2By%3D3%2C%E6%B1%82%26%23189%3Bx%26%23178%3B%2Bxy%2B%26%23189%3By%26%23178%3B%E7%9A%84%E5%80%BC.)
½x²+xy+½y²
=½(x²+2xy+y²)
=½ (x+y)²
=½×3²
=½×9
=9/2
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=½(x²+2xy+y²)
=½ (x+y)²
=½×3²
=½×9
=9/2
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请点击下面的【选为满意回答】按钮.
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