Пошаговое объяснение:

[(x²-10x+25)/(x²-25)]³ ÷[(x-5)/(x+5)]³=1

[(x²-10x+25)/(x²-25)÷(x-5)/(x+5)]³=1

[(x-5)²/(x-5)(x+5) × (x+5)/(x-5)]³=1

[(x-5)/(x+5) × (x+5)/(x-5)]³=1

1³=1

1=1 - тождество доказано