已知x是一元二次方程x2+3x-1=0的实数根那么 [(x-3)除以(3x^2-6x)]除以[(x-2)-5除以x-2]请准确写出算式[(x-3)除以(3x^2-6x)]除以[(x-2)-(5除以x-2)]
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![已知x是一元二次方程x2+3x-1=0的实数根那么 [(x-3)除以(3x^2-6x)]除以[(x-2)-5除以x-2]请准确写出算式[(x-3)除以(3x^2-6x)]除以[(x-2)-(5除以x-2)]](/uploads/image/z/180693-45-3.jpg?t=%E5%B7%B2%E7%9F%A5x%E6%98%AF%E4%B8%80%E5%85%83%E4%BA%8C%E6%AC%A1%E6%96%B9%E7%A8%8Bx2%2B3x-1%3D0%E7%9A%84%E5%AE%9E%E6%95%B0%E6%A0%B9%E9%82%A3%E4%B9%88+%5B%28x-3%29%E9%99%A4%E4%BB%A5%283x%5E2-6x%29%5D%E9%99%A4%E4%BB%A5%5B%28x-2%29-5%E9%99%A4%E4%BB%A5x-2%5D%E8%AF%B7%E5%87%86%E7%A1%AE%E5%86%99%E5%87%BA%E7%AE%97%E5%BC%8F%5B%28x-3%29%E9%99%A4%E4%BB%A5%283x%5E2-6x%29%5D%E9%99%A4%E4%BB%A5%5B%28x-2%29-%285%E9%99%A4%E4%BB%A5x-2%29%5D)
已知x是一元二次方程x2+3x-1=0的实数根那么 [(x-3)除以(3x^2-6x)]除以[(x-2)-5除以x-2]请准确写出算式[(x-3)除以(3x^2-6x)]除以[(x-2)-(5除以x-2)]
已知x是一元二次方程x2+3x-1=0的实数根
那么 [(x-3)除以(3x^2-6x)]除以[(x-2)-5除以x-2]
请准确写出算式
[(x-3)除以(3x^2-6x)]除以[(x-2)-(5除以x-2)]
已知x是一元二次方程x2+3x-1=0的实数根那么 [(x-3)除以(3x^2-6x)]除以[(x-2)-5除以x-2]请准确写出算式[(x-3)除以(3x^2-6x)]除以[(x-2)-(5除以x-2)]
x^2+3x-1=0
x^2-4x-1=-7x,x^2=1-3x
[(x-3)/(3x^2-6x)]/{(x-2)-[5/(x-2)]}
={(x-3)/[3x(x-2)]}/[(x^2-4x-1)/(x-2)]
=[(x-3)/(3x)]/(-7x)
=-(x-3)/(21x^2)
=-(x-3)/[21(1-3x)]
=(x-3)/[21(3x-1)]
=(3x-1-8)/[63(3x-1)]
=(1/63)-8/[63(3x-1)]
解方程x^2+3x-1=0
得x=[-3±√13]/2值代入上式,得
[(x-3)/(3x^2-6x)]/{(x-2)-[5/(x-2)]}
=[-11+√13]/63
或=[13-√13]/63
∵x是一元二次方程x2+3x-1=0的实数根,
∴x2+3x=1,
∴x-33x2-6x÷(x+2-
5x-2)
=x-33x(x-2)÷x2-9x-2
=x-33x(x-2)•x-2(x+3)(x-3)
=13(x2+3x)
=13.
故填空答案:13.
变态