Question

решите эти 2 примера, 7 класс. пожалуйста

Answer 1

$1); ; frac{1}{1-frac{1}{1-frac{1}{x+1}}} = frac{1}{1-frac{x+1}{x+1-1}} = frac{1}{1-frac{x+1}{x}} = frac{x}{x-x-1}=frac{x}{-1}=-x$

$2); ; frac{1}{(x-y)(x-3)}+frac{1}{(y-3)(y-x)} +frac{1}{(3-x)(3-y)} =\\= frac{1}{(x-y)(x-3)} -frac{1}{(y-3)(x-y)} +frac{1}{(x-3)(y-3)} =\\=frac{(y-3)-(x-3)+(x-y)}{(x-y)(x-3)(y-3)} = frac{y-3-x+3+x-y}{(x-y)(x-3)(y-3)} = frac{0}{(x-y)(x-3)(y-3)} =0$