(1)若x+1⼀x=3,求x^2⼀(x^4+x^2+1)的值. (2)若1⼀x-1⼀y=2,求(4

2025-01-19 10:11:14
推荐回答(3个)
回答1:

回答2:


图望采纳

回答3:

(1)
x+1/x=3
x^2+1/x^2 +2 =9
x^2+1/x^2 =7
x^2/(x^4+x^2+1)
=1/( x^2 +1 +1/x^2)
=1/(7+1)
=1/8
(2)
1/x-1/y=2
y-x =2xy
x-y =-2xy
(4x+5xy-4y)/(x-3xy-y)

=[ 4(x-y)+5xy] /[ (x-y) -3xy]
=(-8+5).( -2 -3)
=3/5