代数式=(x²-4x+4)/[(2x-4)(x+2)]
=(x-2)²/[2(x-2)(x+2)]
=(x-2)/[2(x+2)
x=√5
代数式=(√5-2)/[2(√5+2)]
=(√5-2)(√5-2)/2
=(7-4√5)/2