Question

(x-2)(x-3)分之1 - (x-1)(x-3)分之2 + (x-1)(x-2)分之1

注意符号

Answer 1

1/[(x-2)(x-3)]-2/[(x-1)(x-3)]+1/[(x-1)(x-2)]
=[(x-1)-2(x-2)+(x-3)]/[(x-1)(x-2)(x-3)]
=(x-1-2x+4+x-3)/[(x-1)(x-2)(x-3)]
=0/[(x-1)(x-2)(x-3)]
=0

Answer 2

解：原式=[(x-2)-(x-3)]/(x-2)(x-3)-[(x-1)-(x-3)]/(x-1)(x-3)+[(x-1)-(x-2)]/(x-1)(x-2)
=1/(x-3)-1/(x-2)-[1/(x-3)-1/(x-1)]+1/(x-2)-1/(x-1)
=[1/(x-3)-1/(x-1)]-[1/(x-3)-1/(x-1)]
=0