已知若5x²-3x-5=0,求：（1）5x²-2x-1/(5x²-2x-5)；（2）x²+x^-2

已知若5x²-3x-5=0,求：（1）5x²-2x-1/(5x²-2x-5)；（2）x²+x^-2
已知若5x²-3x-5=0,求：（1）5x²-2x-1/(5x²-2x-5)；（2）x²+x^-2

已知若5x²-3x-5=0,求：（1）5x²-2x-1/(5x²-2x-5)；（2）x²+x^-2
5x²-3x-5=0
等式两边同除以5x
x -3/5 -1/x=0
x- 1/x=3/5
5x²-3x-5=0
5x-2x-5=x
5x²-2x- 1/(5x²-2x-5)
=5x²-2x -5 -1/(5x²-2x-5) +5
=x -1/x +5
=3/5 +5
=28/5
x²+ 1/x²=(x-1/x)²+2=(3/5)²+2=9/25 +2=59/25