Question

упростите выражение
$frac{1}{(x-y)(x-3)} + frac{1}{(y-3)(y-x)}+ frac{1}{(3-x)(3-y)}$

Answer 1

1/(x-y)(x-3)-1/(y-3)(x-y)+1/(x-y)(x-3)=(y-3-x+3+x-y)/(x-3)(y-3)(x-y)=0