Question

Nhờ mn giúp ạ, em cảm ơn.

Answer 1

\(D=\dfrac{2\left(a+b\right)}{\sqrt{b}}.\dfrac{\sqrt{b}}{\sqrt{\left(a+b\right)^2}}=\dfrac{2\left(a+b\right).\sqrt{b}}{\sqrt{b}\left(a+b\right)}=2\)

=> Chọn B

Answer 2

Chọn B