Question

2(x+1/x)²-5(x+1/x)+2=0 和x四次方-5x²+4=0

Answer 1

2(x+1/x)²-5(x+1/x)+2=0

(2y-1)(y-2)=0

y1=1/2 y2=2

x+1/x=1/2

x=(1±√15)/4

x+1/x=2

x=1

x^4-5x^2+4=0

(x^2-4)(x^2-1)=0

x=±2

x=±1