已知5x2-3x-5=0,求5x2-2x-1/(5x2-2x-5)的值

已知5x2-3x-5=0,求5x2-2x-1/(5x2-2x-5)的值
已知5x2-3x-5=0,求5x2-2x-1/(5x2-2x-5)的值

已知5x2-3x-5=0,求5x2-2x-1/(5x2-2x-5)的值
5x²-3x-5=0
所以5x²-2x-5=x
5x²-2x=x+5
5x²-5=3x
所以x²-1=3x/5
所以原式=x+5-1/x
=(x²+5x-1)/x
=(3x/5+5x)/x
=3/5+5
=28/5