Question

ДАМ 95 БАЛЛОВ!!! ПОМОГИТЕ!!!!

Answer 1

$1)\ \ \dfrac{k}{(k-7)^2}-\dfrac{k}{k^2-49}=\dfrac{k}{(k-7)^2}-\dfrac{k}{(k-7)(k+7)}=\dfrac{k(k+7)-k}{(k-7)(k-7)(k+7)}=\\\\\\=\dfrac{k^2+6k}{(k-7)^2(k+7)}\\\\\\B=(k-7)(k-7)(k+7)=(k-7)^2(k+7)$

$2)\ \ \dfrac{4}{x(x+10)}+\dfrac{17}{d(10+x)}=\dfrac{4\, d+17\, x}{x\, d\, (x+10)}$

Ответ:  №4 .

$3)\ \ \dfrac{t^2-d}{t}-t=\dfrac{t^2-d}{t}-\dfrac{t^2}{t}=\dfrac{t^2-d-t^2}{t}=\, -\dfrac{d}{t}$

Ответ:  №4 .