初三数学题,已知(x-1/x)²=9/4,则x+1/x=

初三数学题,已知(x-1/x)²=9/4,则x+1/x=
初三数学题,已知(x-1/x)²=9/4,则x+1/x=

初三数学题,已知(x-1/x)²=9/4,则x+1/x=
(x+1/x)²=(x-1/x)²+4
=9/4+4
=25/4
所以：x+1/x=±5/2

开方，正负二分之三

(x-1/x)²=9/4
x^2+1/x^2=17/4
(x+1/x)^2
=x^2+1/x^2+2
=17/4+2
=25/4
所以 x+1/x=5/2或-5/2.