Question

Mọi người giúp em với ạ

Answer 1

a: \(A=\left(a+\sqrt{ab}+b-\sqrt{ab}\right):\left[\left(\dfrac{1}{a^2}-\dfrac{1}{b^2}\right):\left(\dfrac{1}{a}-\dfrac{1}{b}\right)\right]\)

\(=\left(a+b\right):\left(\dfrac{1}{a}+\dfrac{1}{b}\right)\)

\(=\left(a+b\right):\dfrac{b+a}{ab}=ab\)