Question

Rút gọn

Answer 1

\(N=\left(a-b\right)\cdot\sqrt{\dfrac{ab}{\left(a-b\right)^2}}\)

\(=\left(a-b\right)\cdot\dfrac{\sqrt{ab}}{\left|a-b\right|}\)

Vì a<b<0

nên a-b<0

=>|a-b|=-(a-b)

=>\(N=\left(a-b\right)\cdot\dfrac{\sqrt{ab}}{-\left(a-b\right)}=-\sqrt{ab}\)

Answer 2

\(N=\left(a-b\right).\sqrt{\dfrac{ab}{\left(a-b\right)^2}}=\left(a-b\right).\dfrac{\sqrt{ab}}{\left|a-b\right|}\\ =\left(a-b\right).\dfrac{\sqrt{ab}}{-\left(a-b\right)}=-\sqrt{ab}\left(a< b< 0\right)\)