已知9x^2-12xy+4y^2+30x-20y+25=0,求9x^2-12xy+4y^2的值
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![已知9x^2-12xy+4y^2+30x-20y+25=0,求9x^2-12xy+4y^2的值](/uploads/image/z/3763994-50-4.jpg?t=%E5%B7%B2%E7%9F%A59x%5E2-12xy%2B4y%5E2%2B30x-20y%2B25%3D0%2C%E6%B1%829x%5E2-12xy%2B4y%5E2%E7%9A%84%E5%80%BC)
已知9x^2-12xy+4y^2+30x-20y+25=0,求9x^2-12xy+4y^2的值
已知9x^2-12xy+4y^2+30x-20y+25=0,求9x^2-12xy+4y^2的值
已知9x^2-12xy+4y^2+30x-20y+25=0,求9x^2-12xy+4y^2的值
已知9x^2-12xy+4y^2+30x-20y+25=0,
(3x-2y)^2+10(3x-2y)+5^2=0
(3x-2y+5)^2=0
3x-2y=-5
(3x-2y)^2=25
9x^2-12xy+4y^2=(3x-2y)^2=25
9x^2-12xy+4y^2+30x-20y+25=0
(3x-2y)²-10(3x-2y)+5²=0
(3x-2y-5)²=0
即
3x-2y-5=0
3x-2y=5
所以
9x^2-12xy+4y^2
=(3x-2y)²
=5²
=25