Question

7. Упростите выражение: (а/(√ab-b)-√b/(√b-√a))∙((√a-√b)b)/(a+b), а>b, b>0, a≠b

Answer 1

Ответ:

$7)\ \ a>0\ ,\ \ b>0\ ,\ \ a\ne b\\\\\\\Big(\dfrac{a}{\sqrt{ab}-b}-\dfrac{\sqrt{b}}{\sqrt{b}-\sqrt{a}}\Big)\cdot \dfrac{(\sqrt{a}-\sqrt{b})\cdot b}{a+b}=\Big(\dfrac{a}{\sqrt{b}\cdot (\sqrt{a}-\sqrt{b})}-\dfrac{\sqrt{b}}{\sqrt{b}-\sqrt{a}}\Big)\cdot \dfrac{(\sqrt{a}-\sqrt{b})\cdot b}{a+b}=\\\\\\=\dfrac{a+b}{\sqrt{b}\cdot (\sqrt{a}-\sqrt{b})}\cdot \dfrac{(\sqrt{a}-\sqrt{b})\cdot b}{a+b}=\dfrac{b}{\sqrt{b}}=\sqrt{b}$