来自宋进良的问题
【2(x²+1/x²)-9(x+1/x)­­­+14=0】
2(x²+1/x²)-9(x+1/x)+14=0


【2(x²+1/x²)-9(x+1/x)­­­+14=0】
2(x²+1/x²)-9(x+1/x)+14=0
2(x²+2+1/x²)-9(x+1/x)+10=0
2(x+1/x)²-9(x+1/x)+10=0
(2x+2/x-5)(x+1/x-2)=0
2x+2/x-5=0x+1/x-2=0
∴x=2x=1/2x=1