1/x^2+9/(4x^2-4)=1
4x^2-4+9x^2=x^2(4x^2-4)
4x^4-17x^2+4=0
(x^2-4)(4x^2-1)=0
所以
x^2=4或x^2=1/4
从而
x=±2或x=±1/2