=(x-2)(x-3)/(x-3)(x-1)+(x-3)(x-1)/(x-1)²-(x-4)(x+1)/(x+1)(x-1)
=(x-2)/(x-1)+(x-3)/(x-1)-(x-4)/(x-1)
=(x-2+x-3-x+4)/(x-1)
=(x-1)/(x-1)
=1