5x²－3x－5＝0 则 5x²－2x－[1÷（5x²－2x－5）]
问题描述：
5x²－3x－5＝0 则 5x²－2x－[1÷（5x²－2x－5）]
答
5x²－3x－5＝0则，5x²－3x＝5.
5x²－2x－[1÷（5x²－2x－5）]
=5+x-1/(5-5+x)
=5+x-1/x
=(5x+x^2-1)/x
答
5x^2-2x=x+5
5x^2-2x-5=x
所以原式=x+5-1/x
=(x^2+5x-1)/x
条件得到x^2-(3/5)x-1=0
x^2-1=(3/5)x
所以原式=(5+（3/5))x/x=5.6
答
5x²－3x－5＝0∴5x²－2x－5＝x∴5x²－2x－[1÷（5x²－2x－5）]=x+5-1/x=(x²+5x-1)/x=5(x²+5x-1)/5x=(5x²+25x-5)/5x=(5x²-3x-5+28x)/5x=28/5