(1)已知x1,x2是方程x²+3x+1=0的两根,则代数式x1²+8x2+20的值为?(2)已知a,b满足a²=2a+7,b²=2b+7,则b/a+a/b=?(3)已知实数x,y满足4/x⁴-2/x²=3,y⁴+y²=3,则4/x⁴+y⁴的值为?
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![(1)已知x1,x2是方程x²+3x+1=0的两根,则代数式x1²+8x2+20的值为?(2)已知a,b满足a²=2a+7,b²=2b+7,则b/a+a/b=?(3)已知实数x,y满足4/x⁴-2/x²=3,y⁴+y²=3,则4/x⁴+y⁴的值为?](/uploads/image/z/11588248-64-8.jpg?t=%EF%BC%881%EF%BC%89%E5%B7%B2%E7%9F%A5x1%2Cx2%E6%98%AF%E6%96%B9%E7%A8%8Bx%26%23178%3B%2B3x%2B1%3D0%E7%9A%84%E4%B8%A4%E6%A0%B9%2C%E5%88%99%E4%BB%A3%E6%95%B0%E5%BC%8Fx1%26%23178%3B%2B8x2%EF%BC%8B20%E7%9A%84%E5%80%BC%E4%B8%BA%3F%EF%BC%882%EF%BC%89%E5%B7%B2%E7%9F%A5a%2Cb%E6%BB%A1%E8%B6%B3a%26%23178%3B%3D2a%2B7%2Cb%26%23178%3B%3D2b%2B7%2C%E5%88%99b%2Fa%2Ba%2Fb%3D%3F%283%29%E5%B7%B2%E7%9F%A5%E5%AE%9E%E6%95%B0x%2Cy%E6%BB%A1%E8%B6%B34%2Fx%26%238308%3B-2%2Fx%26%23178%3B%3D3%2Cy%26%238308%3B%2By%26%23178%3B%3D3%2C%E5%88%994%2Fx%26%238308%3B%2By%26%238308%3B%E7%9A%84%E5%80%BC%E4%B8%BA%3F)
(1)已知x1,x2是方程x²+3x+1=0的两根,则代数式x1²+8x2+20的值为?(2)已知a,b满足a²=2a+7,b²=2b+7,则b/a+a/b=?(3)已知实数x,y满足4/x⁴-2/x²=3,y⁴+y²=3,则4/x⁴+y⁴的值为?
(1)已知x1,x2是方程x²+3x+1=0的两根,则代数式x1²+8x2+20的值为?
(2)已知a,b满足a²=2a+7,b²=2b+7,则b/a+a/b=?
(3)已知实数x,y满足4/x⁴-2/x²=3,y⁴+y²=3,则4/x⁴+y⁴的值为?
(1)已知x1,x2是方程x²+3x+1=0的两根,则代数式x1²+8x2+20的值为?(2)已知a,b满足a²=2a+7,b²=2b+7,则b/a+a/b=?(3)已知实数x,y满足4/x⁴-2/x²=3,y⁴+y²=3,则4/x⁴+y⁴的值为?
(1)我算出来是(23-11√5)/2 ,或者(23+11√5)/2
(2)2或者-18/7 .这里需要分类讨论的.
(3)等于7.
谢谢慷慨的楼主咯