x^2-4x+4分之x-2 - 2x+4 分之1 - 2x^2-8分之x-1
=(x-2)/(x-2)²-1/2(x+2)-(x-1)/2(x²-4)
=1/(x-2)-1/2(x+2)-(x-1)/2(x+2)(x-2)
=[2(x+2)-(x-2)-(x-1)]/2(x-2)(x+2)
=(2x+4-x+2-x+1)/2(x-2)(x+2)
=7/[2(x-2)(x+2)]