已知x=根号2-1,求(5-6x-3x^2)/(x^2+2x-3)的值.
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已知x=根号2-1,求(5-6x-3x^2)/(x^2+2x-3)的值.
已知x=根号2-1,求(5-6x-3x^2)/(x^2+2x-3)的值.
已知x=根号2-1,求(5-6x-3x^2)/(x^2+2x-3)的值.
x=√2 -1
x+1=√2
(x+1)²=2
x²+2x+1=2
x²+2x=1
(5-6x-3x²)/(x²+2x-3)
=[5-3﹙x²+2x﹚]/[﹙x²+2x﹚-3]
=﹙5-3﹚/﹙1-3﹚
-1