如果(x+ay)(x+by)=x²-4xy+6y²求-3(a+b)-2ab的值
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![如果(x+ay)(x+by)=x²-4xy+6y²求-3(a+b)-2ab的值](/uploads/image/z/13321096-16-6.jpg?t=%E5%A6%82%E6%9E%9C%28x%2Bay%29%28x%2Bby%29%3Dx%26%23178%3B-4xy%2B6y%26%23178%3B%E6%B1%82-3%EF%BC%88a%2Bb%EF%BC%89-2ab%E7%9A%84%E5%80%BC)
如果(x+ay)(x+by)=x²-4xy+6y²求-3(a+b)-2ab的值
如果(x+ay)(x+by)=x²-4xy+6y²求-3(a+b)-2ab的值
如果(x+ay)(x+by)=x²-4xy+6y²求-3(a+b)-2ab的值
x²+(a+b)xy+aby²=x²-4xy+6y²
∴a+b=-4
ab=6
∴-3(a+b)-2ab
=-3×(-4)-2×6
=12-12
=0