Помогите решить пример

Question

Помогите решить пример

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Answer 1

1/ ((x-y)(x-z))    -   1/ ((z-х)(у-х))  = 
= 1/ ((х-у)(x-z) )   -  1/ ( -(x-z) *  -(x-y)) =
= 1/ ((x-y)(x-z))  -    1/ ((x-y)(x-z))=0

Answer 2

1/[(x-y)(x-z)]-1/[-(x-z)*(-(x-y))]=1/[(x-y)(x-z)]-1/[(x-y)(x-z)]=0